Association of Dynamics in Lean and Fat Mass Measures with Mortality in Frail Older Women

The relationship between body composition and mortality in frail older people is unclear. We used dual-x-ray absorptiometry (DXA) data to examine the association between dynamics in whole-body composition and appendicular (4 limbs) and central (trunk) compartments and all-cause mortality in frail older women.

Prospective study with up to 19 years of follow up.

Community dwelling older (≥65) women.

876 frail older participants of the Women's Health Initiative Observational Study with a single measure of body composition and 581 participants with two measures.

Frailty was determined using modified Fried's criteria. All-cause mortality hazard was modeled as a function of static (single-occasion) or dynamic changes (difference between two time points) in body composition using Cox regression.

Analyses adjusted for age, ethnicity, income, smoking, cardiovascular disease, diabetes, stroke, number of frailty criteria and whole-body lean mass showed progressively decreased rates of mortality in women with higher appendicular fat mass (FM) (P for trend=0.01), higher trunk FM (P for trend=0.03) and higher whole-body FM (P for trend=0.01). The hazard rate ratio for participants with more than a 5% decline in FM between two time points was 1.91; 1.67 and 1.71 for appendicular, trunk and whole-body compartment respectively as compared to women with relatively stable adiposity (p<0.05 for all). Dynamics of more than 5% in lean mass were not associated with mortality.

Low body fat or a pronounced decline in adiposity is associated with increased risks of mortality in frail older women. These results indicate a need to re-evaluate healthy weight in persons with frailty. .