In the present study, we show that every year increase in maternal age was associated with a 0.00233 g/cm2 (unstandardized B) decrease in adjusted lumbar spine aBMD, corresponding to about 1.6% of 1 SD (1 SD equaling 0.147 g/cm2) in the offspring. Assuming a linear relationship, e.g., a 15-year difference in maternal age would correspond to a difference in about 24% of a standard deviation in lumbar spine aBMD. The possible effect is hardly of any clinical significance on the individual level, but if maternal age continues to rise, a shift in the

distribution of BMD in the offspring population could be the result, which could lead to an increased MK2206 incidence BAY 11-7082 cell line of osteoporosis in the future. In the present study, we found an association between

advancing maternal age and reduced bone mass in the offspring, even though we included a large number find more of known confounders. Social position is a parental characteristic that has previously been shown to be positively related to bone mass acquisition in 10-year old children as a consequence of enhanced gain in height [17]. In our material, the adult height of the GOOD subjects was positively correlated to bone density and bone mineral content, while the socioeconomic index (SEI) was not, and maternal age remained an independent predictor of bone mass in the offspring also after adjusting for SEI. Adult height, however, was shown to be a negative independent predictor when including all variables correlated to aBMD at the lumbar spine in the linear regression analysis. Maternal height has been shown to predict

hip fracture risk in a Finnish study [18]. Inclusion of maternal height did not either alter the obtained results in the present study. This was however only possible to test for in a large subsample of the subjects (n = 705). Furthermore, inclusion of several known predictors, such as physical activity, calcium intake, and height and body composition parameters did not explain the association between bone parameters in the offspring and maternal age. A Canadian Mirabegron study has shown an association between delayed childbearing and low birth weight [19], which in turn has been shown to be a predictor of bone mass later in life, mediated largely by bone size [20]. In our cohort, there was, however, no correlation seen between maternal age and birth size, i.e., birth weight and height. Length of pregnancy showed a weak negative correlation with maternal age but was of no importance when included in the regression analysis. Other possible explanations, which we have not been able to adjust for, may be found in placental function, partly reflected though in birth anthropometrics, or other aspects potentially affected by maternal aging such as the environment in utero. One might also speculate in epigenetic causes.