Despite higher bone mineral density (BMD), women with obesity are at increased risk of fracture versus normal-weight women. Optimal adolescent bone accrual is critical for normal peak bone mass and future bone health. We examined bone accrual over a year in young women with moderate to severe obesity (OB) versus normal-weight controls (NWC).
We assessed 21 OB and 50 NWC 13-25 years old at baseline and one year. Dual-energy X-ray absorptiometry was used to assess areal BMD (aBMD) and high resolution peripheral quantitative CT (distal radius and tibia) to assess volumetric BMD (vBMD), bone geometry and microarchitecture. Analyses were controlled for age and race.
OB and NWC were similar for age, race, height, and physical activity. OB vs. NWC had higher BMI (p<0.0001), but younger menarchal age (p=0.022). Over one year, total hip BMD-Z scores decreased in OB and increased in NWC (p=0.02). Increases in radial cortical area and thickness, and total and cortical vBMD were lower in OB than NWC (p≤0.039). Groups did not differ for tibial parameters.
We demonstrate that longitudinal bone accrual is impaired at the total hip and radial cortex in young women with obesity, raising concerns regarding their future bone health.