Utilizing the Shell Health Surveillance data, this study assesses the impact of obesity, one of the most prevalent health risk factors, on employee illness absence and long-term mortality.


A ten-year follow-up (1994-2003) of 5026 Shell Oil employees was conducted to assess the impact of obesity on illness absence frequency rate and workdays lost. The impact of obesity on mortality was based on a 20-year follow-up (1984-2003) of 7139 middle-aged Shell employees. Relative risks (RR) for selected causes of death by body mass index (BMI) category (normal: BMI=18.5-24.9, overweight: 25.0-29.9, and obese: 30+ kg/m2) were calculated using the Cox regression model adjusted for age, gender, and smoking status as well as other risk factors, i.e., cholesterol, hypertension, and fasting blood glucose.


Obese employees had higher absence rates and missed more workdays compared to employees with normal weight. For example, employees less than 50 years of age who were overweight or obese missed an average of 4.0 and 5.7 workdays per year, respectively, as compared to 2.9 days of employees with normal weight. Similar patterns were noted for those 50 years and older (7.3 and 9.6 vs. 6.2 days). In addition, obese employees have significantly increased absence for diseases such as circulatory, respiratory and digestive systems, musculoskeletal disorders, and injuries. Compared with employees with normal weight, obese employees had a statistically increased risk of dying for all causes (Relative Risk [RR]=1.25), coronary heart diseases (RR=2.29), cardiovascular diseases (RR=2.22), diabetes (RR=16.97), and accidents (RR=2.64).


This study found a positive association between obesity and both absence frequency and workdays lost as well as the risk of dying from a number of causes. Reductions of employee obesity prevalence may be an effective means of improving employees' health and increasing a company's productivity.

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