Body mass index is inversely related to mortality in older people after adjustment for waist circumference.
OBJECTIVE
To examine the individual and combined influence of body mass index (BMI) and waist circumference (WC) on mortality risk in older people.


METHODS
Longitudinal cohort study.


METHODS
Cardiovascular Health Study, a longitudinal study of cardiovascular disease and its risk factors in older people.


METHODS
Five thousand two hundred men and women aged 65 and older.


METHODS
BMI and WC were measured at baseline. The risks of all-cause mortality associated with BMI and WC were examined using Cox proportional hazards models over 9 years of follow-up.


RESULTS
When examined individually, BMI and WC were both negative predictors of mortality, but when BMI and WC were examined simultaneously, BMI was a negative predictor of mortality, whereas WC was a positive predictor of mortality. After controlling for WC, mortality risk decreased 21% for every standard deviation increase in BMI. After controlling for BMI, mortality risk increased 13% for every standard deviation increase in WC. The patterns of associations were consistent by sex, age, and disease status.


CONCLUSIONS
Higher BMI values indicated a lower mortality risk once the risk attributable to WC was accounted for, whereas higher WC values indicate a higher mortality risk once the risk attributable to BMI was accounted for. Both BMI and WC should be measured in the clinical setting, but in older adults higher BMI is associated with lower mortality rates.
Janssen
Ian
I
School of Physical and Health Education, Queen's University, Kingston, Ontario, Canada. janssen@post.queensu.ca
Katzmarzyk
Peter T
PT
Ross
Robert
R
D000368:Aged; D000369:Aged, 80 and over; D001824:Body Constitution; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009026:Mortality; D009765:Obesity / Q000401:mortality; D050177:Overweight; D016016:Proportional Hazards Models; D012307:Risk Factors; D014481:United States / Q000453:epidemiology