1. Introduction
The importance of estimating economic cost of obesity and the obesity-related conditions in the United States is not only important for the insurance providers but also for the policy makers involved in the state and federal health programs. Actuaries showed much interested in estimating the economic cost of obesity in the United States. Two major publications
Alves et al. (
2021) and
Behan and Cox (
2010) by the working groups of Society of Actuaries (SOA) are the evidence of these efforts, while these studies focus on the estimation of costs due to obesity based on the publicly available data they lack some considerations. These approaches do not examine possible margin of error related to the estimation of costs. Building a predictive model with the purpose of forecasting the future costs due to obesity is important for life and health actuaries working for insurance and reinsurance companies, government agencies, and regulators. The actuaries in these sectors are expected to recognize if there is any significant gap in the insurance coverage and develop potential solutions as well as mitigation and adaptation strategies to manage risk and profitability of the health insurance providers.
It is estimated that obesity-related medical costs alone account for nearly
$150 billion annually (
Adult Obesity Facts 2021) in the United States. Those who are obese are seen to take an increased number of sick days, have decreased productivity, and are more likely to develop a mobility disability, all of which add to the overall costs as
Wolf and Colditz (
1998) noted. From a financial perspective, understanding the trends of obesity provides a way of measuring and addressing this epidemic.
For actuaries working in the healthcare insurance sector,
Brown and McDaid (
2003) identified obesity as one of the several underwriting risk classification factors that can be used to estimate mortality-driven benefits. Obesity itself is responsible for many diseases and health conditions causing indirect impact on absenteeism and excess mortality in the workforce. In 2018, 42.4% of Americans were considered obese, 9.2% being severely obese, with future statistics projected to be even more severe by the Centers for Disease Control and Prevention (
Adult Obesity Facts 2021). Obesity is linked to many serious diseases, namely coronary heart disease (CHD), hypertension, gallbladder disease, breast, endometrial and colon cancer, and osteoarthritis (
Wolf and Colditz 1998), which can complicate the visible impact of obesity risk. Moreover, the effects of obesity incur a large cost not only as it relates to money spent on treatment of obesity itself and related diseases, but also costs that impact employment and productivity, while the health insurance premium has doubled in the past ten years, it is unclear how much of this premium is sufficient to cover the financial burden of the obesity pandemic. Any potential gaps would indicate the need for additional expansion of state and federal health programs for managing the obesity pandemic. The evaluation of existing and developing new health coverages related to obesity-related conditions is an important consideration for the profitability of the health insurance providers.
The analysis of the costs of obesity requires some specificity and precision with the terminology used to describe both the methods and approaches in cost estimation. First, the definition of obesity is typically linked to the Body Mass Index (BMI) defined as person’s weight in kilograms divided by the square of height in meters. Despite some criticism (see
Romero-Corral et al. (
2008),
Miljkovic et al. (
2017)), the BMI is still widely used in many epidemiological studies and the individuals are categorized into weight groups as underweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), and overweight (25 ≤ BMI < 30). To be consistent with the CDC and the World Health Organization, in this paper we are interested in the obesity category, or those individuals whose BMI is at least 30. Second, we define obesity-related costs in two categories: direct and indirect, as seen in
Figure 1. Direct costs are medical costs spent to treat obesity. Indirect costs are those incurred as a result of obesity, other than treatment itself.
When determining direct costs for a particular disease, there are two general approaches: prevalence-based and incidence-based economic evaluations, seen in
Figure 2. A prevalence-based economic evaluation analyzes the costs of a disease for an entire population over the duration of a specific timeline, i.e., typically one year (
Mauskopf 1998). An incidence-based economic evaluation focuses on the costs incurred by a predetermined group, often called a cohort, for the duration of the disease itself (
Mauskopf 1998). Since obesity is a risk factor for so many other conditions, it is necessary to determine the extent to which obesity risk is responsible for these related conditions. This is done by looking at the extent of a condition in a group of obese individuals, and comparing it to that of a group of normal weight individuals, while controlling for various other factors. This process is known as finding the population-attributable risk percent (PAR%) or attributable case percent (
Wolf and Colditz 1998).
The objectives of this paper are as follows:
Develop a top-down approach for the estimation of the state-level economic costs of obesity risk for the time period 1996 to 2018.
Employ the bootstrapping method to estimate the average economic cost of obesity per person, including the 95% confidence intervals.
Propose the forecasting models that will estimate the future costs of obesity by state over a 3-year period.
Compare the total economic cost of obesity relative to the aggregated health premium and annuity considerations from the Schedule T of the Annual Statement for year 2018.
Previous studies on the topic of the costs of obesity each take different approaches, but the core terminology is universal. In the next subsection, we review several important studies in this area of research.
Literature Review
Several important studies were reviewed in the area of economic cost estimation related to obesity and morbidity.
Wolf and Colditz (
1998) performed an estimate of the economic cost of obesity in the United States, estimating
$99.2 billion in 1995. The authors conducted a prevalence-based approach to examine diseases in which obesity was a noticeable risk factor to derive an estimate for the direct cost of obesity. The PAR% was estimated for these diseases to approximate the proportion of the costs that were attributable to obesity. The indirect costs associated with obesity was estimated based on the data from the National Health Interview Survey, and the results were trended using the Consumer Price Index to report costs in 1995 dollars.
Thorpe et al. (
2004) used the data from the 1987 National Medical Expenditure Survey and the 2001 Medical Expenditure Panel Survey, Household Component to create a two part regression model. This model took into account a range of covariates, including but not limited to weight, health insurance status, income, and region. Per capita spending was estimated by producing cost estimates simulating if all people were underweight, normal weight, overweight, or obese. Doing so “nets out the impact of observable individual characteristics (such as age, insurance status, income)” (
Thorpe et al. 2004). The analysis was done for 1987 and 2001, utilizing unique models for each year. Additionally, a large part of the contribution of the study was to decompose the spending growth of obesity into what was attributable to changing obesity rates, and what was attributable to increased per capita spending. The finding was that 27% of the increase in costs from 1987 to 2001 were due to the increase in the rate of obesity and spending, while the study does provide a more dynamic perspective by showing a change in costs over time, the length of time between the chosen years is quite large. Therefore, the year-to-year fluctuations of spending due to obesity are not seen, making it difficult to rule out other confounding factors during that time frame.
Behan and Cox (
2010) reviewed a larger body of work, looking at obesity and its connection to diseases as well as its relevance to mortality and morbidity, ending with an analysis of the cost of obesity. Upon reviewing nearly 500 articles on the topic, their study concluded that the overall cost in the United States and Canada was approximately
$300 billion per year for medical costs, disability, and excess mortality caused by obesity. The study used a weighted approach to get a general risk value for each of the respective diseases that obesity is linked to, then combined that with the expenditures listed on the Medical Expenditure Panel Survey to get a cost estimate. The breadth of the study is substantial, but lacks deeper actuarial analysis where statistical models can be employed to assess the error in estimation for their produced cost estimates.
Hammond and Levine (
2010) identified four main categories of economic impact due to obesity: direct medical costs, productivity costs, transportation costs, and human capital costs. All are sizeable, but the largest of these categories are direct medical costs and productivity costs, while the estimates given from the different studies vary, the authors agreed with a similar conclusion: the cost of obesity is substantial and impacts a wide array of areas. The discussion about the direct medical costs and productivity costs, specifically absenteeism, presenteeism, and disability costs, clearly have an impact on the overall cost of obesity. Transportation costs and human capital accumulation are also discussed, and while it may be argued that obesity has an effect on these costs, the connection of obesity is tangential at best. It is not completely discernible whether obesity is a driving factor in the costs, or if there is merely a correlation in its presence.
A time series model by
Revels et al. (
2017) forecasted the change in prevalence of those considered overweight, obese, and morbidly obese, as well as the overall healthcare costs in the United States. The 2019 forecast for healthcare costs was
$3.6 trillion, and encompasses all healthcare costs, not just those related to obesity. The obesity healthcare costs in the study, however, were estimated as 10% of total healthcare costs, which is a generalization from varying predictions without considering the state variation in the cost estimates. When looking at the costs of obesity over a longer period, it may not be realistic to assume that obesity-related costs remain a set fraction of the overall healthcare costs. It is especially important to make distinctions of costs related to obesity between years when there is a rapidly evolving landscape such as it is now. The proportion of people who are obese is rising steadily, so the amount spent on obesity is likely to rise as well; however it is not clear whether the increase will be directly proportional. Additionally, social media ploys have saturated outlets to promote experimental treatments and “quick fixes”, which indicates that there is a sizeable increase in expenses toward new weight loss strategies. Thus, it is prudent to recognize these changes as study limitations in the estimation procedure.
The most recent study by
Alves et al. (
2021) builds on the previous study by
Behan and Cox (
2010) with a focus on examining the latest trends in obesity and developing an estimate of obesity’s impact on morbidity, productivity loss from disability and productivity loss from premature mortality in the United States and Canada.
Alves et al. (
2021) estimated the total morbidity cost of
$177.9 billion in 2019 for the United States and Canada with the United States bearing
$172.0 billion of that total cost. Morbidity costs are examined by age band and sex across different classes of obesity prevalence. The authors considered state-level, by-age, per-capita estimates for lost income, lost earnings, supplemental security income payments, and absenteeism costs in 2019 dollars, but these are also merely point estimates.
The following outlines the order of the paper.
Section 2 summarizes the methodology for building the state-level obesity-related cost data as well as the exponential smoothing models for the cost estimation and forecasting by state.
Section 3 includes the data validation and comparisons of our results to those reported by the existing studies.
Section 4 provides the analysis of the data including the cost estimation and forecasts by state.
Section 5 discusses limitations of this study.
Section 6 provides the concluding remarks.
3. Data Validation and Comparison with Existing Studies
In this section, we analyze and validate the obesity-related cost data developed using methodology presented in
Section 2. These actual costs serve as an input in modeling the future obesity-related costs, thus it is important to cross check and validate our cost calculations with several other sources and explain any observations using tangible events in the United States. This also helps fortify the credibility of the input data itself for building a reliable statistical model for forecasting future cost.
Figure 4 shows the time series of the various obesity-related costs for the period 1996 to 2018. We observe a sharp increase in the total cost that almost triples during this time period reaching the level of
$420 billion of dollars in 2018. Both direct and indirect costs follow a similar upward trend over time with a different intercept. In 1996, the indirect cost was
$42.5 billion and the direct cost was
$14.5 billion. Then, in 2018, the indirect and direct costs reached
$257.3 billion and
$165.1 billion, respectively. The gap between these two types of costs increased over time.
Since 1996, there were three years that showed a decrease in the medical cost of diseases related to obesity. The first and largest decrease of 9% happened in 1998 as a result of the Balanced Budget Act of 1997. In an effort to achieve a fully balanced budget by 2002, the goal of the act, costs and welfare needed to be cut so that the government could return to solvency (
Schneider 1997). One of the consequences of this effort was that there was a severe decrease in Medicare spending, which takes up a large portion of overall medical spending. Therefore, a decrease would be expected because there is less financing available to the general population, and in turn, people who utilize the aid.
Another moderate dip of 5% in medical costs is observed in 2013. At this time there was slower growth overall in the health insurance industry, both with private and public care.
Hartman et al. (
2015) argued that this trend was caused by impacts from, “slower growth in enrollment, the impacts of the Affordable Care Act (ACA), and the federal budget sequestration of 2013” (
Hartman et al. 2015, p. 150). Therefore, a combination of factors contributed to the overall medical insurance environment being less robust in 2013, which explains the moderate dip, but not a complete collapse.
Finally in 2015, there was an additional decrease of 2% as a result of the ACA.
Schubel and Broaddus (
2018) reported “from 2013 to 2015, the nationwide uninsured rate fell 35 percent” (
Schubel and Broaddus 2018, p. 2). Because of this, a great increase of 15% was seen in 2014. However, since the observation of costs are year-to-year, the 2015 numbers were unlikely to keep up with the growth rate from 2014, since that is when the biggest reduction in uninsured individuals was seen. Therefore, the slight decrease is reasonable since it is in response to a readjusting landscape after experience a surge of new participants.
Table 3 provides cost estimates of the different cost categories as found in the reputable studies. The first column cites the published study from which the estimate came. The second column shows the year for which the reported estimate was computed. The third column presents the estimate, in billions of dollars, generated by the cited study. For example, the study by
Ward et al. (
2021) reported
$172.7 billion in direct cost for 2019. This estimate is comparable to the estimate of
$172.0 billion reported by
Alves et al. (
2021) for the same year.
Table 4 shows the summary of our cost estimates for 2018. The total cost attributable to obesity is estimated in the range of
$422 billion and is broken down by several categories. The last column of this table shows the 95% bootstrap prediction interval for the cost per person. Cost per person for each category is computed at the state level. Then, a sampling distribution based on 10,000 bootstrap samples is developed for each category of cost. To better qualify the accuracy of our generated per-person cost estimates, we believe it is necessary to report the cost within an interval rather than a point estimate. These 95% prediction intervals represent our bounds at the 95% prediction level for the per-person direct and indirect costs, given the constants used in the cost equations. They are not in attempt to assess the uncertainty within the constants used within the equations themselves.
Figure 5 shows the bootstrap sampling distributions of the direct and indirect costs per person with their corresponding 95% prediction interval.
In order to put our estimate of
$422.4 billion into perspective, we compare it to some other economic indicators. According to the report published by U.S. Bureau of Economic Analysis (see
U.S. Bureau of Economic Analysis (
2019)), the current dollar USA GDP in 2018 was estimated to be
$20.50 trillion. National health care spending in 2018 was estimated at
$3.6 trillion which is about 17.5% of the national GDP or
$11,172 per person (see
Health Affairs (
2019)). Our total estimated cost of obesity represents about 2% of the 2018 USA GDP. It is important to note that there are other costs (i.e., pharmacy costs, out-of-pocket payments, cost of public Medicare programs, etc.) associated with obesity that are not included in our estimate. Therefore, our estimate is most likely closer to the lower bound of the true value of the total obesity-related cost. However, considering the complexity of the problem, the lack of publicly available data in this domain, and the amount of uncertainty involved, the true value of all obesity-related costs is almost impossible to know.
It is necessary to discuss the differences in estimation methods when comparing figures across different studies so that any imbalance between estimates in the table can be understood. For example, in
Finkelstein et al. (
2003), which is cited by
Tsai et al. (
2011) as being a “high-quality study”, their estimate of the 2003 direct medical costs was
$26.8 billion, whereas the study mentioned by
Thoenen (
2002) estimated these costs to be
$39.0 billion in 1995 dollars. This seems counterintuitive, since it has been seen that direct medical costs tend to increase over time. However, there is a difference with what figures the studies produce.
Finkelstein et al. (
2003) has clearly broken down the portion of calculated costs that are attributable to obesity only, not overweight. This significantly reduced the estimate of the study from
$51.5 billion to the reported
$26.8 billion. Yet, some studies are less precise in their definition of costs. For instance, some studies report figures as they are attributable to obesity, but it is unclear whether these also include a portion of costs from the overweight group as well. Additionally, it appears that some studies employ different methodologies. Thus, we believe that the discrepancies between figures for similar years are due to the mentioned variations between the studies.
Finkelstein et al. (
2003) reported two different direct costs for obesity:
$26.8 and
$47.5 billion. The paper goes on to explain that the two estimates were produced using separate data sources for costs. The estimate of
$26.8 billion was derived from the MEPS data and the other relied on data from the National Health Accounts (NHA). The two sources have a different emphasis. The NHA data include nursing home expenditures, which as mentioned before are out of the scope of our study. This further illustrates that while studies may be calculating the same costs, the scope of the data that are being utilized are very important as well and not always immediately apparent when reviewing others’ research.
The 1996
Wolf and Colditz (
1998) estimate for direct cost was not listed because the distribution of the study’s costs were reviewed by a study from Columbia University, and found to be somewhat inaccurate (
Thoenen 2002). They concluded that the “higher mortality rates of obese persons decrease[s] direct medical costs; because of this, however, the indirect costs of obesity may be larger than originally estimated due to lost productivity” (
Thoenen 2002, See Executive Summary). Thus, after the revision of the costs, the direct costs are likely lower and indirect costs are likely higher. Therefore, only the total cost estimate for this study was used, since it does not rely on the distribution of costs between direct and indirect categories.
Still, the estimate for the direct medical cost from
Thoenen (
2002) is quite different than our estimate. Again, this has to do with the fact that there is some difference in the definition of direct medical cost. The study by
Wolf and Colditz (
1998) looked at the, “preventive, diagnosis, and treatment services related to the disease (e.g., hospital and nursing home care, physician visits, medications)” (
Wolf and Colditz 1998, p. 98). Our study relies on the total reported medical costs by disease for each year, which “include payments for medical events reported during the calendar year” (
MEPS 2021, See Notes), while this is more vague than what is outlined in the study by
Wolf and Colditz (
1998), it likely excludes the costs of nursing home care, certain preventative measures, and the cost of over-the-counter drugs. Therefore, the estimate that we have to go off of observes a different scope of costs. However, with this information, we can then find our estimate to be more reasonable, since we would expect an exclusion of cost categories to decrease cost estimates.
Moreover, the discrepancy between the
Wolf and Colditz (
1998) estimate of 1996 Indirect Costs is likely due to a difference in cost considerations. Our estimate includes costs from excess mortality, absenteeism, and disability, whereas the comparable cost is “lost output as a result of a reduction or cessation of productivity due to morbidity or mortality” (
Wolf and Colditz 1998). Therefore, there is no consideration of disability costs. Furthermore, if our estimate for the costs of disability in 1996 (
$14.5 B) are subtracted from the total indirect costs estimated (
$42.0 B), the result is much more comparable (
$27.5 B).
Alves et al. (
2021) published per capita estimates as well as overall costs due to obesity for 2019. The study takes yet another approach toward defining the cost categories uniquely. For example, the category most analogous to direct costs is morbidity, which includes, “the cost for services such as doctor visits, hospitalization and prescription drug utilization” (
Alves et al. 2021, p. 15). Therefore, although this is a more general definition, it seems to line up relatively well with what our study examines for direct costs. The definition of excess mortality is very comparable to how it is defined in our study. However, for the other indirect costs within the paper, the definitions of the disability and absenteeism categories are different from those in our study. In fact,
Alves et al. (
2021) defines disability costs to include presenteeism and absenteeism, whereas our study defines them distinctly. Therefore, for those individual cost subcategories, our estimates are not very comparable. Yet, when the overall costs are taken into consideration, we get results that are somewhat similar. The reported morbidity cost is
$172.0 billion, whereas our direct costs are
$168.4 billion, when using our 2018 estimate trended forward a year by the medical inflation rate from 2018 to 2019. For indirect costs, the reported cost is
$211.8 billion, whereas our estimate is
$263.2 billion, while this estimate is further from the reported cost estimate, as mentioned there is more of a significant difference in the definition of the cost categories for indirect costs. Thus, after recognizing these differences, the report validates our estimation methods.
Figure 6 shows how the cost changes across the United States for the different time periods: 1998 (top), 2008 (middle), and 2018 (bottom). The intensity of darker color is associated with the higher level of the estimated cost. Five regions are created on each map based on the following grouping of the state cost in billions of dollars: <1, 1–2, 2–5, 5–10 and >10. The intensity of darker color is associated with the higher level of the estimated cost. No states had a cost estimate over
$10 billion in 1998. By 2008, the cost raised above
$10 billion in four states-California, Florida, Texas, and New York. In 2018, this list of states is expanded to include also Illinois, Ohio, Pennsylvania, North Carolina, Virginia, Michigan, Georgia, and New Jersey. The increase in population combined with the increase in cost is slowly affecting a large portion of the Unites States.
Obesity is also recognized as a global health problem so it is important to discuss several studies conducted outside of the United States. Other countries around the world are also experiencing problems with obesity, mainly those that are economically developed. According to a review study done by
Helble and Francisco (
2020), many countries in Asia are rapidly growing in their prevalence of adults with obesity, and the estimate of obesity-related costs is about 0.78% of the region’s GDP, while the prevalence of obese adults in these countries is still significantly lower than that of the United States, a growing overweight population will likely lead to an increased obese population as well. In Europe a study by
Müller-Riemenschneider et al. (
2008) finds that “relative economic burdens ranged from 0.09% to 0.61% of each country’s GDP”. In a study done by
Boachie et al. (
2022), it was found that about 0.67% of South Africa’s GDP is attributable to the combined impact of overweight and obesity. Another review study by
Duran et al. (
2019) found that in Latin America, there could be a wider range of obesity-related costs as a percent of each country’s GDP, from 0.54% in Chile, up to 2.5% in Mexico. Therefore, even on a national scale, obesity is a pressing issue, and pervades virtually all economically developed countries. More research into the costs included within each of these figures is necessary so that an equal comparison can be made across the various regions.
4. Cost Estimation and Forecasts
In this section, we present the results of the long-term cost estimation and forecasts by state. Since the time series by state exhibit a strong increasing trend we consider three exponential smoothing methods: Holt’s linear trend only, the damped Holt’s method, and the simple exponential smoothing.
The model building is performed in two steps which include training and testing. The training step is referred to as the learning step. In this step, the three models are built on 21 years of data. Cross validation and forecast accuracy is evaluated using the test set created on the last two years of data allowing for a true assessment of the forecasting ability by comparing the out of sample errors. The damping parameter is selected, the value that generates the results with the most accuracy or least Root Mean Squared Error RMSE the Mean Absolute Error (MAE).
Figure 7 provides the side by side box-plots of the RMSE and the MAE across the three methods. We observe that the simple exponential smoothing has the worst performance among the three methods as it does not capture the trend well. Holt and the damped Holt method have similar performance based on RMSE and MAE with Holt’s being a bit superior. The distribution of RMSE and MAE for the Holt and damping Holt methods generate several outliers. These outliers indicate larger RMSE and MAE for their respective states (NY, TX, OH for Holt’s and damped Holt’s method; as well as FL for the damped Holt’s method). A detailed summary of the RMSE results by state across three methods for 2018 is provided with
Table A1 in the
Appendix A.
Table 5 provides the summary of the Holt’s trend and the damped Holt’s forecasts with their corresponding 95% and 99% prediction intervals for 2018. The actual values shown in the second column of this table are the 2018-cost by state computed using the method described in
Section 2. Both forecasting methods tend to underestimate the true value for most of the states. Additionally, both methods produce nearly the same estimate for 2018 total costs (about
$393 billion). However, the damped model offers more consistency into the future, as the current trend is expected to be damped in later durations. Obesity-related public policies have already been implemented at the federal and state levels, and we expect they would slow down the growth of the obesity pandemic. This aligns with the future trends of obesity, as we are approaching 50% prevalence of obesity in the adult population and the sharp increase in obesity from year to year is less likely to continue. Therefore, we adopt the damped Holt’s method for out of sample forecasts.
Table 5 also includes the
results by state for year 2018. We see that most values are between 0.15 and 0.25, with an average of 0.24. This means that our calculated total costs of obesity are about 1/4 of overall health premium costs, on average.
The future 3 year forecasts are summarised in
Table 6 with their 95% prediction intervals. Based on this forecast, we observe that the national level obesity-related cost will reach level of
$451 billion of dollars. An increase of over 7% would be expected over the 3-year period. The top five states with the highest costs are: California, Texas, New York, Florida, and Illinois (for all 3 years). Illinois is 6th in population, but 5th for overall cost. The other four states are the most populous.
It should be noted that the prediction intervals included in
Table 5 and
Table 6 are a reflection of the uncertainty in the forecasting of future costs. A visual representation of these intervals is shown in
Figure 8, which depicts the 99% prediction intervals for the 2018 damped Holt’s forecast by state ordered from highest to lowest magnitude of point estimate. The estimated actual cost values, as denoted with the symbol (x) are shown in relation to the prediction intervals. These estimated actual values are computed based on the methodology presented in
Section 2. We observe that all estimated actual values are contained within the forecasted 99% prediction interval.
5. Study Limitations
As is with any large-scale analysis using aggregated data, there are several limitations to this study. We are going to discuss several of them but we acknowledge that this list may be exhaustive. The primary limitation is the uncertainty related to the input variables, while the data sources themselves are reputable, the metrics being used from these sources are not entirely objective. For example, the data related to BMI and obesity prevalence by state rely on participants to self-report their heights and weights, which can lead to the self-reported bias. Moreover, the constants acquired for the cost calculations are based off of estimates as well, and there can be some disconnect when deriving constants calculated in one context and applying them to another, while there was concentrated effort to minimize the effects of these uncertainties, they still exist and must be acknowledged.
Another limitation of the study was the utilization of a proxy to distribute national costs between states. As outlined, this study uses each state’s population count as a ratio to the national population count to scale the direct costs. This approach distributes national costs among the states using the most accurate metric we can find on a state level. However, we recognize that state population count is not completely analogous to the difference in medical costs between states. One could possibly consider building medical inflation indexes and using those in the cost distribution from a national level to the state level (see
Dhaene and Hanbali (
2019)). However, further efforts toward obtaining state-level demographics, payer information, and product-specific costs would be required, as the cited work observes inflation in Belgium. Thus, the same methodology could be applied to augment this study, but a more comprehensive effort would be needed.
Moreover, as mentioned in
Section 2, this study only observes 3 types of indirect costs. Other studies have examined more of these costs, which would contribute to a greater overall indirect cost, but the costs examined in this paper were deemed to be the most important and impactful to the usefulness of our findings.
People at risk of obesity may have higher out-of-pocket costs. Pharmacy costs related to prescription drugs are also higher for overweight and obese people and these costs are not included in our estimate. Most state insurance plans are required to cover certain services with no cost-sharing, including obesity screening and counseling for all adults and children (see
Jannah et al. (
2018)). The Affordable Care Act was passed in 2010 and offered a reduction in health care costs while simultaneously providing the means of obtaining health insurance. For people at risk of obesity, Medicaid extension includes coverage for bariatric surgery on a state-by-state opt-in basis, increasing insurance coverage of the highly-effective bariatric surgery. However, there is still a need to increase insurance coverage as well as to develop health-related policies that will overcome the societal and cultural barriers to bariatric surgery use (see
Brooks et al. (
2021)). Thus, additional costs associated with the bariatric surgeries are not considered in this estimation.
Among many factors that influence the increase in the level of obesity are the quality of food, children’s nutrition in kindergartens and schools, agricultural production and policies, food processing, etc. However, our study does not evaluate the economic impact of these factors.
We recognize that it is now 2022 and the most future projections from our study are only through 2021. However, it is important to note that there is a lag of approximately three years in the availability of the obesity prevalence data used to produce estimates and projections. This is a necessary lag, as there are many factors that contribute to the prevalence of obesity by state. The majority of these factors can be seen in the diseases associated with obesity. When initially processed, for example, a case of cardiovascular disease may not at first be linked to obesity, but then after further treatment or tests, etc. it is discovered that the initial episode was linked to obesity. Therefore, in order to have a comprehensive view of the impact of obesity in more recent years, it is necessary that only years with completed data be used. Still, these results are relevant with regard to two principal factors: data validation and trend monitoring. As is with all uncertain outcomes in the future, we have no way to definitively determine what the prevalence nor cost of obesity will be in the coming years. We can use sound statistical methods to produce our best estimates for these outcomes, but they primarily rely on historical data, and therefore are not necessarily reflective of future events. Therefore, by having three years of predictions, as newer data becomes available, the resulting cost estimates can be compared to the previous cost predictions to assess whether the cost of obesity is rising more rapidly year over year than expected. In this way our predictions can be used as a sort of baseline for how we expect costs to grow.
Finally, it is important to impose a qualifying statement on the forward trends of this data, due to the COVID-19 Pandemic. There are likely many changes to see in the cost structure of obesity in the United States. This could be seen through a change in the type of treatment sought out, the de-prioritization of treating non-emergent conditions, or a myriad of other impacts that are obscured from the data we currently have available. These possibilities are not examined in this study, and therefore offer a promising area of follow-up on this research.
6. Discussion and Conclusions
In this paper, we developed the state-level direct and indirect costs attributable to obesity in the United States for the time period 1996 to 2018. The direct cost consists of direct medical costs and indirect costs. The indirect cost includes the costs associated with absenteeism, disability, and excess mortality.
Our study suggests that the total cost attributed to obesity is estimated to a level of $422 billion as of 2018 (95% CI for the cost per person: [$3596, $3624]), representing about 2% of the national GDP for the same year. By 2021, we forecast that this cost will reach the level of $475 billion. The 2018 costs of obesity for indirect costs are estimated at $257.3 billion (95% CI for the cost per person: [$2198, $2201]) and direct costs are estimated at $165.1 billion (95% CI for the cost per person: [$1398, $1423]). In order to eliminate the impact of inflation, all cost estimates are expressed in the value of 2018 dollars.
Having the 23 years of cost data by state, we then employed the exponential smoothing methods to generate the 3-year-ahead forecasts by state. To provide further analysis, as well as to serve as a check, we compared the 2018 estimates to the health premiums from Schedule T of the Annual Statement in the insurance industry by introducing the Obesity-related Cost Ratio (OrCR). This allowed us to roughly gauge how much insurance premium can be attributable to overall obesity costs, which help to demonstrate the impact of obesity costs on the insurance industry. The calculation of the OrCR is excluded for California due to the lack of health premium data for that state.
All data sources used in this report are publicly available. For the purpose of forecasting the future cost, we have selected the damped Holt method as it performs the best among a few other methods used in the model development. We have utilized the bootstrapping method to develop the 95% prediction intervals for the cost per person. The 95% prediction interval for the total obesity-related cost per person is [$3596, $3624] as of 2018. Our results present the most comprehensive evaluation of the cost due to obesity at the state level and we hope that our study will provide the motivation for additional discussion and research related to the obesity pandemic.
At the state level, our estimate of the obesity-related costs is still significantly lower than the health insurance premium. A possible avenue for future research would be to investigate if the relationship between the premium and cost is sustainable in the long run.
Actuaries may be interested in studying the smartwatch data related to the health and physical activities of their policyholders, assuming their consent. This would be especially important for people at risk of obesity. Health-related data are already used in several research areas. A study conducted by
Seifert and Vandelanotte (
2021) investigated the extent to which adults aged 65 and older in Switzerland utilize mobile health tracking tools in everyday life. The survey of 1149 adults showed that mobile device users were significantly more open to sharing their data with medical or research institutions than non-users of mobile devices. The authors found that the older adults reported substantial levels of smartphone and tablet use but fairly low levels of fitness tracker, smartwatch, and health-related app use. A large number of participants were willing to share health-related data, encouraging findings that can be used to promote a similar study targeting younger age groups. By monitoring physical activity via smartwatch data, an insurance company may be able to study the lifestyle of insured people at risk of obesity and monitor their physical activity, and explore pricing options according to the “Pay-as-you-live (PAYL)” insurance. However, for a successful implementation of PAYL insurance,
Wiegard et al. (
2019) emphasized the importance of multi-party agreements (insurance companies, service providers, and manufacturers of wearables) in order to arrive at solutions for more data security and data protection before implementing further features of the devices. The same study reported that the influence of perceived privacy risk on perceived value among German insureds is almost twice as high as that of perceived benefit. A similar study can be conducted in the United States to obtain clarity about critical success factors from a people-at-risk perspective and therefore insights for insurance companies.
Besides PAYL insurance, actuaries may investigate what other benefits enhance the perceived value such as adding monetary compensation (discounts, coupons, bates, or health promotions)as an additional benefit factor to motivate the policyholders at risk of obesity to undertake regular physical activities.
Chapman (
2012) reported that health promotion represents one of the most effective strategies for reducing medical costs and absenteeism as well as reducing the average sick leave, health plan costs, and workers’ compensation and disability insurance costs.
Finally, our cost predictions for years 2020 and 2021 can be used as another baseline for how we would expect the costs of obesity to progress in the absence of the COVID-19 pandemic. Again, when the actual numbers for those years are available, they can be compared to the predictions from this study to determine how large of an impact the COVID-19 pandemic had from what we would expect to see. Further investigation into the links between COVID-19 and obesity from a cost standpoint would be needed to offer an informed perspective on this topic.