The Impact of Obesity on Illness Absence and Productivity in an Industrial Population of Petrochemical Workers

Purpose

Examine employee illness absence and the economic impact of overweight and obesity in a petrochemical industry workforce.

Methods

A 10-year follow-up (1994–2003) of 4153 Shell Oil Company employees was conducted. Absence frequency rates and average number of workdays lost were calculated for normal weight, overweight, and obese employees with and without the presence of additional risk factors. The study also assessed the change in overweight and obesity prevalence in the study population and estimated the current and future economic impact of these conditions.

Results

Overall, obese employees were 80% more likely to have absences (24.0 vs. 13.3 per 100 employees) and were absent 3.7 more days (7.7 vs. 4.0 days) per year compared with those employees with normal body weights. Among employees with no additional risk factors, overweight employees lost more than 1.5 times more days (4.2 vs. 2.6 days) per year, and obese employees more than 2.5 times more days (7.2 vs. 2.6 days) compared with their normal-weight colleagues. Similarly, absence frequency attributable to cardiovascular disease significantly increased among employees with one or two additional risk factors present, such as smoking, high blood pressure, or hypercholesterolemia. The direct cost of illness absence from overweight and obesity for this study population was $1,873,500. Furthermore, 31% of the total illness absence was attributable to overweight and obesity in 1994, and the percentage had risen to 36% by 2003.

Conclusions

The economic impact to employers is great and will continue to rise unless measures are taken, particularly to reduce the number of employees moving from overweight to obesity with time.

Introduction

Overweight and obesity have steadily increased throughout Europe and the United States. The World Health Organization European Region has seen the prevalence of obesity (body mass index [BMI]) ≥ 30.0 kg/m²) triple in the last 20 years (1). The prevalence of obesity in the United Kingdom, approximately 13% among men and 16% among women in 1993, steadily increased to about 25% in both genders in 2004 (2). When the prevalence of both overweight and obesity is considered, a staggering 76% of men and 69% of women had BMIs ≥ 25 kg/m² in 2005 (1). In The Netherlands, the prevalence of obesity increased among men from 4% in 1981 to 10% in 2004 and doubled from 6% to 12% among women (3). In 2005 the prevalence of overweight and obesity (BMI ≥ 25 kg/m²) in The Netherlands was 62% in men and 55% in women (1). The prevalence of obesity among Danish adults more than doubled between 1987 and 2001 among men from 5.6% to 12.5% and from 1.4% to 9.0% among women (4). If the prevalence of obesity in the WHO European Region continues to increase at the same rate as in the 1990s, there will be an estimated 150 million obese adults in the region by 2010 (1). In the United States, the prevalence of obesity remained about 15% in adults between 1960 and 1980 (5). However, through the late 1980s and early 1990s, obesity continued to climb and more than doubled to 31% by 2000 (6). By 2015, an estimated 87% of men and 83% of women are expected to be overweight or obese (1).

The current cost of obesity is estimated to represent 2% to 7% of all national health expenditures worldwide (7). In England, the cost to the National Health Service is about 1 billion pounds per year (or approximately 1.8 billion U.S. dollars in 2005) and an additional 2.3 to 2.6 billion pounds in estimated indirect costs to the UK economy. The currently increasing trend translates to an annual cost to the economy of approximately £3.6 billion per year by 2010 (8). Several studies have estimated the average annual obesity-related medical costs in the United States to be between 5% and 7% of annual health care expenditures 9, 10, 11, 12 or about $70 billion in 1995 (13). The prevalence of obesity in the U.S. workforce has increased by 44% in the last 10 years, and nearly 30% of all workers are considered obese (14). Obesity-related absenteeism cost U.S. employers $2.4 billion in 1998 (15).

Whereas research has long established the association between health risk factors and various health end points, only more recently has the relationship between health risks and business outcomes been explored. One business outcome of interest is productivity, or more specifically the loss of productivity as a result of illness-related absences.

Illness absence in a working population is a complex phenomenon, influenced by many factors such as age, gender, education, personal health risk factors, and work-related factors. Numerous studies have examined the relationship between modifiable health risks and employee absenteeism (16). Studies have shown that overweight and obese employees have significantly higher absence rates 17, 18, 19, 20. A few studies have also explored the relationship between the number of health risk factors and absenteeism, and some have demonstrated increased absenteeism with the accumulation of health risk factors 18, 20, 21, 22.

While several studies have examined the relationship between health risk factors and absenteeism, most are based on a cross-sectional study design and/or survey data. Very few studies have used a prospective study design and objective (i.e., not self-reported) health risk and absence data. In the current study, prospectively collected employee physical examination and illness absence data was used to examine the influence of obesity prior to the reported illness absence. The purposes of this study were to (1) assess and quantify absence frequency rates and the average number of workdays lost attributable to overweight and obesity with and without the presence of additional risk factors and (2) to assess the economic impact of overweight and obesity in a petrochemical industry workforce.