16 May 2022
Pregnancy has been considered a risk factor for developing osteoporosis. Although there has been much research in the field of bone health, the relationship between parity and bone mineral density (BMD) is still controversial. Recently, Yang et al.  reported the results of a cross-sectional study that used data from the National Health and Nutrition Examination Survey (NHANES) in order to investigate the relationship between parity and BMD of the femoral neck and lumbar spine in 924 postmenopausal women aged 45 to 65. The authors applied three linear regression models, Model 1 (unadjusted), Model 2 (adjusted for age and body mass index, and Model 3 (adjusted for all covariates). Also, the p value trend of BMD in the different parity groups was mutually verified with the results of multiple regression. Multiple logistic regression models were used to assess the relationship between parity and osteoporosis. After adjustment for potential confounders, women with a parity of ≥ 6 had significantly lower BMD at the lumbar spine than women with a parity of 1-2 (β = - 0.072, 95% CI: - 0.125, - 0.018, p = 0.009). Despite this, there was no correlation found between parity and femoral neck BMD in any of the three regression models. Furthermore, parity of ≥ 6 was associated with a significantly higher prevalence of lumbar spine osteoporosis compared to parity 1-2 (OR = 3.876, 95% CI: 1.637, 9.175, p = 0.002). The authors conclude that after adjusting for BMD-related risk factors, in postmenopausal women, a parity of 6 or more was associated with decreased lumbar spine BMD but not femoral neck BMD. Authors suggest that postmenopausal women with high parity are at increased risk of lumbar osteoporotic fractures and should pay more attention to their bone health.