Relationship Between Weight-Adjusted Waist Index and Osteoporosis in the Senile in the United States from the National Health and Nutrition Examination Survey, 2017-2020

Background: Some studies suggested obesity may be beneficial in preventing bone loss through the negative relationship between body mass index (BMI) and osteoporosis in senile. However, using BMI to measure obesity is unconvincing due to confounding factors such as muscle mass were not taken into account, and few articles have yet taken a better way to evaluate the relationship between obesity and osteoporosis. Methodology: Using a cross-sectional sample of 1,979 participants aged ≥65 years from the National Health and Nutrition Examination Survey (NHANES) 2017 to 2020, we evaluated the relation of weight-adjusted waist index (WWI) with osteoporosis. WWI was calculated as waist (cm) divided by the square root of body weight (kg). Diagnosis of osteoporosis was described as follows: according to the updated reference for calculating bone mineral density T-Scores, we marked the BMD value as X, using the formula T femoral neck= (X g/cm2-0.888 g/cm2)/0.121 g/cm2, T lumbar spine= (X g/cm2- 1.065 g/cm2)/0.122 g/cm2, and defined those with a final T femoral neck <-0.25. T lumbar spine<-0.25 or patients with previously diagnosed OP in other hospitals as osteoporosis. Results: All the 1,979 participants were between 65 and 80 years, there were 379 (21.1%) with osteoporosis, 608 (30.7%) with WWI exceeding 12 (cm/√kg) (range 8.85-14.14), and 955 (48.3%) women. Furthermore, the relationship between WWI and osteoporosis was nonlinear with a threshold effect point. Odds of OP significantly increased with the increase of WWI (OR 2.33, 95% CI 11.48–3.38, P = 0.0001) at the right side of the threshold point (WWI≥12) according to the threshold effect study. Conclusions: Found a significant positive relationship between WWI and osteoporosis. Body fat management in the senile may be good to prevent osteoporosis if confirmed by other prospective studies analyzing the longitudinal risk of osteoporosis with obesity.