BMI-for-age percentile curves for older adults.

Objective: The objective of this manuscript is to present BMI-for-age percentile curves for men and women aged 45 to 90 years.

Methods: Weighted empirical percentile estimates were calculated using data from the Canadian Longitudinal Study on Aging (CLSA) comprehensive cohort (2011-2018) according to age and sex. Statistical smoothing procedures were used to generate smoothed curves for the percentile values. Overweight and obesity were defined as BMI greater than the 85th and 95th percentile for age and sex, respectively.

Results: In order to create BMI-for-age percentile curves, n = 56,705 observations were used (n = 29,961 individuals at baseline and n = 26,744 individuals at the first follow-up visit). In men, absolute values for BMI percentiles are lower than those in women, and the decline in BMI begins earlier (i.e., at a younger age). In women, the 95th percentile threshold for BMI is highest between ages 59 and 67 years (i.e., 41 kg/m), and in men, the 95th percentile threshold for BMI is highest between ages 51 and 62 years (i.e., 39 kg/m).

Conclusions: BMI-for-age percentile curves demonstrate how an individual's BMI value compares with values from a reference population comprising individuals of the same age and sex. This approach has widespread utility to determine eligibility for interventions and as a tool to incorporate into clinical models of care for obesity management in an aging population.