The Effect of Three-year Weight History on Quantitative Ultrasound Parameters in Older Mainland Chinese Women and Men

Abstract

Title: The Effect of Three-year Weight History on Quantitative Ultrasound Parameters in Older Mainland Chinese Women and Men Background: Finding risk factors for poor bone quality that are relevant to China is useful for targeting higher-risk women for bone quantitative ultrasound (QUS) testing. Weight history has typically been measured as the difference in weight between two time points. Incorporating an additional indicator of weight variability over this time period may enhance this measure. Objective: To examine the relationship between bone QUS and weight history (including weight variability) in pre and postmenopausal women, women transitioning into menopause (TIM) and men over 65 years of age. Methods: This was a retrospective, clinic-based study of 1201 postmenopausal, 862 pre-menopausal and 419 TIM women, and 424 older men in Guangdong Province, China. Weight was measured yearly over a three year period. Weight history over 3 years was defined as (1) weight trend (the slope of weight on year) and weight variability (the root mean square error (RMSE) around the slope of weight on year) (2) weight trajectories (3-year trajectories estimated by growth mixture modeling), and (3) weight change (the percent change in weight from baseline). Stiffness index (SI) of the os calcaneus [assessed using a Lunar Achilles Insight QUS device (GE Medical Systems Inc., USA)], age, height and weight were measured once at the end of year 3. Z-scores were used to compare regression lines for predicting SI from the weight history variables among study groups. Results: Weight variability (weight-RMSE) was significantly and negatively associated with SI, independent of weight, weight trend, age and height (β = -1.32; P< 0.03) among postmenopausal women. No other associations between weight history and SI were detected. Slopes for the association between SI and weight-RMSE were not significantly different between postmenopausal women and the other study groups. Conclusions: This study provides evidence that measuring weight variability, in addition to weight change, may provide a more complete assessment of the influence of weight history on bone. Further work is needed to investigate methods of quantifying weight variability that could be used in a clinical setting.