Self-reported general health and Body Mass Index: a U-shaped relationship?

A sizable literature demonstrates an increased likelihood of self-reported poor health with increasing Body Mass Index (BMI). A U-shaped relationship between BMI and health is evident in research but it is not believed that the health of people who are underweight gets the attention it deserves. The relationship between BMI categories and poor general health including those persons who are underweight has been investigated.

Cross-sectional study.

Data were obtained from the Health Survey for England pooled for 2006-08 to provide a sample of 26,596 adults aged 16-74 in a series of binary logistic regression models to determine the likelihood of people reporting their general health as being poor.

A clear U-shaped relationship between BMI and health has been found for controlling for individual level demographic, socio-economic and health-related behaviour variables and area deprivation.

The literature largely focuses on the relationship between obesity and health and this is understandable given that many more persons are obese than are underweight. A person who is underweight is about as likely to report poor general health as a person who is obese.