The Obesity Paradox

Obesity has prolonged the lives of elderly diabetics

Denis Strigun, Naked Science

Experts from Beijing Metropolitan Medical University have confirmed the hypothesis of the obesity paradox in the largest sample of patients with diabetes mellitus.

According to According to the World Health Organization (WHO), from 1980 to 2014, the number of obese people worldwide doubled. In addition to the deterioration of the quality of life, overweight is a risk factor for many non-communicable diseases, such as heart disease, cancer and type 2 diabetes, with a mortality rate of up to 12 percent. It is known that obesity is characteristic of the vast majority (85 percent) of patients with diabetes, while weight normalization allows them to normalize their metabolism and increase insulin sensitivity. However, the relationship of body weight with mortality is unclear. The main hypothesis assumes a positive correlation of indicators.

Meanwhile, a number of observations do not find a link between obesity and mortality in diabetes. In turn, some studies reveal a negative trend: with an increase in body weight, the probability of early death of patients (but not of a healthy population) may decrease. The phenomenon formed the basis of the hypothesis of the "obesity paradox", which is also supported by statistics of people with chronic heart failure and kidney disease. However, despite the increase in the number, such reports remain contradictory. To fill the gap, Chinese scientists conducted a meta-analysis of 20 articles that were published in peer-reviewed scientific journals until December 2014.

The review included data on the survival of patients (separately – in the case of cardiovascular complications) with diabetes mellitus, depending on body mass index (BMI). The sample consisted of 250,016 people, the duration of observations was 2.9–16.7 years. The reliability of the conclusions of the original publications was additionally checked using a modified Newcastle-Ottawa scale to assess the risk of systematic errors. The results showed that a significant reduction in the likelihood of early death was found only among older patients and in the short term. Thus, raising the age by a year reduced the risk of death from any cause by 2.5 percent.

Prolongation of observations for a year, on the contrary, was associated with an increase in the risk of death by 3.2 percent. Curiously, in the case of heart disease, the negative dynamics turned out to be more pronounced. Using the example of 19,643 diabetic patients, the authors concluded that being overweight reduces the likelihood of early death from cardiovascular diseases by 15 percent. Moreover, normal body weight did not contribute to such survival. According to scientists, the trend did not depend on the individual characteristics of the body. The work complements the available data on the obesity paradox and is consistent with the 2003 review, which also revealed a reduction in risk in patients over 65 years of age.

Article by Gao et al. Impact of obesity on mortality in patients with diabetes: Meta-analysis of 20 studies including 250,016 patients published in The Journal of Diabetes Investigation.

Portal "Eternal youth" http://vechnayamolodost.ru  13.06.2017