Overweight : Overweight - Consequences for individual and society

Obesity is a key risk factor for a number of diseases

Although obesity could be considered a disease in its own right, it is also a key risk factor for a number of chronic diseases that constitute the principal causes of death in the EU. Obesity, especially central obesity, is an important risk factor for cardiovascular disease (CVD), type 2 diabetes mellitus and certain cancers. Overweight and obesity contribute significantly to osteoarthritis, a major cause of disability in adults.

Other conditions associated with obesity are infertility among women, mental problems such as depression and low self-esteem and sleep apnoea.

Obesity and type 2 diabetes mellitus: a close relationship

One of the consequences of weight gain is insulin resistance, which can result in type 2 diabetes mellitus. Obesity, in particular abdominal obesity, is the most important risk factor for the onset of diabetes. Compared with the lowest BMI category, risks for developing type 2 diabetes mellitus are increased more than tenfold among women with BMIs higher than 29 kg/m²and among men with BMIs higher than 31 kg/m2 (Carey et al., 1997; Visscher & Seidell, 2001). Being moderately overweight is also closely related to the onset of type 2 diabetes mellitus. About 64% of type 2 diabetes in North-American men and 74% in North American women could be avoided if there were no BMIs above 25 kg/m2 (WHO, 2000; Visscher & Seidell, 2001). See also the EUphocus Diabetes prevention and care.

Overweight is related to several cancers

Overweight, in particular obesity is related to the incidence of some cancers. The strongest evidence is for cancer of the endometrium. A BMI exceeding 30 kg/m2 is associated with a one and a half to three times higher risk of developing endometrial cancer than a BMI between 20 and 25 kg/m²(WCRF, 1997; Visscher & Seidell, 2001). The WCRF classifies the relationship between high BMI and breast and kidney cancer as “probable”, with approximately 1.8-fold higher risk for those with a BMI exceeding 27 kg/m² compared with those having a BMI below 17 kg/m². Furthermore, there is evidence of a possible relationship between high BMI and colon cancer. This relationship is more consistent for men than for women. Gallbladder cancer is possibly associated with high BMI, particularly for women.

A possible mechanism for the relationship between high body weight and cancer is based on the metabolic abnormalities (metabolic syndrome) that result from high BMI levels (Visscher & Seidell, 2001).

Effects of overweight on cardiovascular health

The effects of obesity on cardiovascular disease are manifold. Hypertension is probably one of the most common ones. Blood pressure increases with the increase of BMI, and people who are obese have been found to have a much higher prevalence of hypertension (AIHW, 2004).

Relative risk highest for women with obesity

An overview of relative risks for diseases associated with obesity is presented in Table Estimated increased risk for the obese of developing associated diseases. The data are extracted from The National Audit Office (NAO) in England (NAO, 2001). A more extensive overview of relative risks for the different BMI levels is given in the report ‘Our food, our health - Healthy diet and safe food in the Netherlands’ (Kreijl et al., 2006). Based on international literature, risks have been estimated for different age classes, both sexes and different levels of overweight. From this overview it becomes clear that morbidity is elevated in overweight people and that it is higher in obese people than in overweight people. This is particularly true of type 2 diabetes, but also holds for cardiovascular diseases, gallbladder diseases, conditions which impaired mobility (such as osteoarthritis), and various forms of cancer.

Indirect costs of obesity are far greater than direct costs

The direct costs of obesity are now estimated to be around 1% - 5% of total health care costs in Europe, compared to 7% (or US$ 70 billion) in the United States (Colditz, 1999; Seidell, 1995).
Indirect costs, which are far greater than direct costs, include work days lost, physician visits, disability pensions and premature mortality.

Narbro calculated that approximately 10% of the total costs of the productivity losses due to sick leave and work disability may be attributable to obesity-related diseases (Narbro et al., 1996). Due to the increase in prevalence and costly consequences, obesity is now being recognised not only as a risk factor in the clinical setting but also as an important threat to public health. The public health impact of obesity should be measured by its combined effect on disability and mortality. Intangible costs such as impaired quality of life are also enormous.

Wilk EA van der (RIVM). Overweight - Consequences for individual and society. In: EUPHIX, EUphact. Bilthoven: RIVM, <http://www.euphix.org> EUphact\ Determinants of health\ Biological and personal factors\ Overweight, 28 April 2008.

Literature and data sources

AIHW, Australian Institute of Health and Welfare (AIHW) and National Heart Foundation of Australia. The relationship between overweight, obesity and cardiovascular disease. AIHW Cat. No. CVD 29. Canberra: AIHW (Cardiovascular Disease Series No. 23). 2004.

Carey VJ, Walters EE, Colditz GA, Solomon CG, Willett WC, Rosner BA, et al. Body fat distribution and risk of non-insulin-dependent diabetes mellitus in women. The Nurses' Health Study. Am J Epidemiol, 1997; 145(7): 614-9.

Colditz GA Economic costs of obesity and inactivity. Med. Sci. Sports Exerc., 1999; 31 S663: 67.

Kreijl CF van, Knaap AGAC, Raaij JMA van (eds). Our food, our health - Healthy diet and safe food in the Netherlands. [Ons eten gemeten - Gezonde voeding en veilig voedsel in Nederland]. 364 p in English. RIVM, 2006; report 270555009.

NAO, The National Audit Office. Tackling Obesity in England. Report by the comptroller and auditor general. London: The Stationery Office, 2001; HC 220 Session 2000-2001: 15 February 2001.

Narbro K, Jonsson E, Larsson B, Waaler H, Wedel H, Sjöström L Economic consequences of sick-leave and early retirement in obese Swedish women. Int. J. Obes. Relat. Metab. Disord, 1996; 20: 895-903.

Seidell JC. Obesity in Europe: scaling an epidemic. Int J Obes 1995; 19 (suppl. 3): S1-S4.

Visscher TLS, Seidell JC. The Public Health Impact of Obesity. Annu. Rev. Public Health, 2001; 22: 355-375.

WCRF, World Cancer Research Fund. Food, Nutrition and the prevention of cancer: a global perspective. Washington 1997.

WHO, World Health Organization Obesity: preventing and managing the global epidemic. Report of WHO expert consultation (June 3-5, 1997) WHO TRS 894 2000.