BMI, ageing tied to adiposity

Age and BMI both have influence on adiposity, with varying effects depending on the type of adipose tissue (AT), suggests a study.

Four hundred healthy, community-dwelling individuals aged 22‒83 years were included in this study. The investigators used MRI to measure proton density fat fraction (PDFF) of the lumbar spine (L2‒L4) bone marrow AT (BMAT), the psoas major and erector spinae (ES) muscles, and the liver. They also measured abdominal total AT, visceral AT (VAT), and subcutaneous AT (SAT) areas at L2‒L3 levels via quantitative CT.

Partial correlation analysis was carried out to explore the association of each AT variable with age and BMI. In addition, multiple linear regression analysis was conducted to assess each AT variable as a function of age and the other independent AT measurements.

Of the 168 men included in the analyses, 29 percent had normal BMI (<24.0 kg/m²), 47 percent had overweight (24.0‒27.9 kg/m²), and 24 percent had obesity (≥28.0 kg/m²). In women, the corresponding BMI proportions were 46 percent, 32 percent, and 22 percent.

Total AT, VAT, and SAT showed strong or very strong associations with BMI in both men and women, while BMAT and ES PDFF exhibited a robust association with age in women and a moderate correlation in men. BMAT PDFF was associated with age but not with any of the other AT depots, while psoas PDFF correlated with ES PDFF but not with age or other AT depots.

In addition, liver PDFF was associated with BMI and VAT and was slightly associated with SAT in men. VAT and SAT correlated with age and with each other in both men and women.