Mortality Risk of High BMI in Life Insurance Applicants and the US Population

This study seeks to quantify the mortality effect of high levels of body mass index (BMI) on life insurance applicants and participants in the National Health and Nutrition Examination Survey (NHANES) in univariate models and in successive models controlling for BMI-related diseases and conditions.

It is well established that a high BMI is associated with increased all-cause and cardiovascular mortality; however, the quantitative effect of controlling for related diseases and conditions is not well understood.

Data were collected from over 7 million life insurance applicants submitting samples to Clinical Reference Laboratories (CRL) and 23,486 NHANES participants with available BMI and mortality status. Cox models were utilized, treating BMI as both a continuous predictor and as a categorical variable within various age and sex groups. Six Cox models were constructed in each age-sex-data group: a univariate model controlled only for age, then 5 more successively controlling for disease status (hypertension, diabetes, and heart disease), liver function tests, blood pressure/renal function, and finally hemoglobin A1c.

Overall, the effect of high BMI on mortality hazard was highest in the univariate model, and lower with successively controlled models. In the life insurance data, the residual effect of BMI in the final models was still significant above a BMI of about 35. In the NHANES data, the effect remained significant only above a BMI of about 40. In the continuous models, the hazard of BMI was persistently significant for both sexes in the CRL models, only for men in the final NHANES model.

Based on this study, the effect of high BMI on mortality is significantly blunted when accounting for diseases and conditions that are associated with high BMI.