Body composition of older adults with normal body mass index. Cross-sectional analysis of the Toulouse Frailty clinic.

BACKGROUND

Body mass index (BMI) determines general corpulence and health, whatever age, sex or clinical background. Normal BMI (18.5-24.9 kgm2) is defined as healthy, normal, weight leading to a false impression that no intervention is needed.

OBJECTIVES

Assess the prevalence of body impairments in the presence of normal BMI.

DESIGN

Cross-sectional design. Bivariate and a multivariate regression analysis assessed the association of body composition with clinical parameters in the presence of normal BMI.

SETTING

Community dwelling older adults attending the Toulouse Frailty Clinic at the University Hospital, Toulouse.

PARTICIPANTS

876 community dwelling, autonomous older adults, 70 years and over.

MEASUREMENTS: Dual X-ray Absorptiometry (DXA) assessment, and cognitive, physical, nutritional, and demographic evaluations were included in the present analysis.

RESULTS

Of the initial sample, 347 (39.61 %) patients had normal BMI, and among them, 152 (43.80 %) had low lean mass, 144 (41.49 %) were osteoporotic and 2 (0.58 %) increased fat mass. A poor nutritional status (Mini-Nutritional Assessment score, MNA-score, <24) was the only independent variable associated with body impairments in the presence of normal BMI (Odd Ratio 2.83; 95 % Confidence Interval 1.64-4.89).

CONCLUSION

Nearly 70 % of the adults with normal BMI had at least one impairment in body composition (low lean mass, osteoporosis, or obesity). In the light of the present study, older adults with normal BMI and an MNA-score under 24 should be assessed with DXA to identify the age-associated impairments in body composition in order to lead to specific interventions.