Genetic and Physiological Factors

Genetic factors

Genetic factors, such as a single gene defect are exceptionally rare and cause childhood onset obesity. The most common disorder is Prader- Willi syndrome and children who have this condition develop a voracious appetite.

Physiological Factors

It has been suggested that there are differences within a population in the susceptibility to become obese if the environmental conditions are right. However, the “susceptibility” or “thrifty” gene leads only to a latent tendency and does not lead to obesity without the effect of other factors, which are encompassed in a modern, urban lifestyle that exists in the Western world. According to some studies, a genetic predisposition to obesity occurs in around 70% of the population.

Also, recent studies have been undertaken to explain factors such as the reasons for the excess coronary heart disease risk in South Asian immigrants from the Indian subcontinent and the high prevalence of insulin resistance and diabetes. The conclusion, in one study, was that exposure to increased fat intake and obesity related to migration is likely to be an explanation for the high prevalence of coronary heart disease risk factors in Gujaratis in Britain.

In another study, it concluded that there was a predisposition to insulin resistance and its associated metabolic abnormalities, which appeared to be genetically determined and that environmental changes have an effect to a lesser degree.

In the UK, a study has indicated that British Afro-Caribbean and Pakistani girls are at increased risk of obesity while Indian and Pakistani boys are more likely to be overweight. Many studies have shown the increased impact of abdominal obesity at a lower BMI in individuals of South Asian descent.

There is generally a higher rate of obesity in women than men (although there is probably a higher prevalence of overweight in men) with obesity occurring more commonly after marriage and with increasing numbers of children.

Amended April 2008