In 1952 Lester Breslow called for action on the new health problem of overweight in the US population. Citing evidence that America’s health, based on mortality of white adult males, lagged behind other Western countries, he concluded that the excess premature mortality in US men was closely linked with overweight and that reduction in overweight was accompanied by reduction in mortality. Breslow’s 1 paper compared differences in mortality rates of men over 45 years of age in the US with men in five other countries; Canada, Denmark, New Zealand, Norway, and Sweden. The age-standardized death rates were significantly higher in the US relative to the other countries, particularly for cardiovascular-renal disease (CVRD) and all-cause mortality. The highest difference was seen between the US and Norway; with US mortality rates over 30% higher. The differences were mostly attributable to CVRD death rates (1852 deaths in the US vs 877 in Norway per hundred thousand men over 45 years). Breslow proposed that excess bodyweight was a key cause of this premature mortality in US men. The paper described the effect of different levels of bodyweight on standardized mortality rates. The analysis, based on actuarial tables of the Metropolitan Life Insurance Company, should be seen as an important first step in establishing the effect of increasing levels of weight on a range of non-communicable diseases. Breslow identified that the definition of ‘normal weight’ then used by the insurance industry was misleading, since chronic disease mortality rates were higher in those considered of normal weight than those considered underweight. He indicated that ... ‘even a little overweight; 5–14% above normal, induces a substantially increased mortality rate’, especially in diabetes and cardiovascular diseases. It shows that even in post-war America the average weight based on population normal values was associated with ill-health and excess mortality. Breslow called for the introduction of the term ‘optimal’ rather than normal weight based on a bodyweight associated with lowest mortality rates rather than population means. It is clear that there was already scepticism about the causal link between overweight and disease incidence and mortality in 1952. It was obvious that not everyone who was overweight acquired diabetes and CVRDs. However, data at that time highlighted that incidence for these conditions was higher among overweight individuals. Breslow proposed that a precautionary approach should be taken; suggesting that it was reasonable to recommend that avoiding being overweight would reduce the risk of premature death. This was supported by early evidence of a reduction in mortality risk, observed in overweight individuals who lost weight, analysing data from the Metropolitan Life Insurance Company (1925–34). Insured clients who were overweight had much higher mortality compared with normal weight individuals and were being charged higher insurance rates. Some individuals who lost weight re-applied to the company to have their insurance premiums reassessed. The information presented by Dublin and Marks 2 was compelling, finding that the mortality rate in those who had lost weight was lower than the mortality rate in those who remained overweight (hazard ratio of 0.70 for men and 0.74 for women). As consultant to the President’s Commission on Health Needs of the Nation, Breslow proposed that overweight was ‘a major public health problem’. He suggested two main approaches should be adopted to prevent this condition; popularizing public health messages on the need to attain an optimal weight; second, evaluating the effectiveness of a range of obesity intervention programmes. He also proposed the need for more research into the relationship between excess weight and increased mortality, and for better measures of overweight itself. Fifty-three years later, it is sobering to reflect on Breslow’s recommendations. Most positively it can be seen that scientific understanding of the relationship between overweight and obesity and disease risk has significantly improved. Obesity is now recognized to be associated with an increase in many health problems, some of which primarily impact on quality of life such as exertional breathlessness, musculo-skeletal and skin problems, and infertility, while others increase the risk of premature death, including non-insulin dependant diabetes, gall bladder disease, cardiovascular disease (hypertension, stroke, and coronary heart disease), hepatoesteatosis, and certain types of cancers. 3 Severe obesity affects life expectancy; 8.7% of deaths in the UK 4 are estimated to be due to excess weight, with life expectancy 9 yrs lower for obese people than non-obese. The health consequences for children are less clear but a systematic review shows that childhood obesity is strongly associated with cardiovascular risk factors and diabetes in childhood, which persist into adulthood, overweight children become overweight adults, and there is significant psychological morbidity. 5 1 Department of Epidemiology and Public Health, London School of Hygiene and Tropical Medicine, University of London, UK. 2 Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, University of London, UK.
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Jun 1, 2023
Robert C Tasker 
Open Access