Among the 124 young women, 64 (51.6%) were current (n = 50) or previous smokers (n = 14). The use of contraceptive

pill for more than 3 months concerned 24 (19.4%) young women. There was no significant difference between girls with (n = 96) and without (n = 28) birth weight and infant weight in terms of BMI, femoral neck aBMD and distal tibia pQCT values at the mean age of 20.4 years. At birth and at 1.0 year of age, there was no relationship between future menarcheal age, taken as a precise assessment of pubertal timing, and BMI (Table 2). In contrast, highly significant inverse regression coefficients (ß) were recorded at the age of 7.9 and 8.9 years, i.e., when all girls were still prepubertal as indicated in the legend Alisertib order in Table 1. The inverse regression coefficient still became maximally negative at the age of 12.4 year (ß = −0.455, P < 0.001). At this age, MENA explained 18% of the BMI variance (R 2 = 0.18) (Table 2). Afterwards, the negative slope regression of BMI on MENA was less steep, but still remained statistically significant at the beginning of the third decade (Table 2). Table 1 Anthropometric and femoral neck aBMD data from birth to 20.4 years in healthy girls Age (year/s) Weight

Height BMI FN aBMD kg cm kg/cm2 mg/cm2 Birth 3.2 ± 0.4 49.3 ± 2.1 13.0 ± 1.2 NA  n = 115 1 9.2 ± 0.9 73.9 ± 3.4 16.9 ± 1.4 NA  n = 96 7.9 ± 0.5 26.5 ± 4.1 127.7 ± 5.9 16.2 ± 1.8 634 ± 74  n = 124 8.9 ± 0.5 29.8 ± 4.9 132.7 ± 6.1 16.9 ± 2.1 Selleckchem MK-2206 647 ± 75  n = 123 10.0 ± 0.5 33.2 ± 5.7 138.8 ± 6.7 17.1 ± 2.1 675 ± 78 Methocarbamol  n = 114 12.4 ± 0.5 44.5 ± 8.1 153.8 ± 7.9 18.7 ± 2.5 751 ± 103  n = 106 16.4 ± 0.5 56.8 ± 7.9 164.0 ± 6.2 21.1 ± 2.7 867 ± 111  n = 113 20.4 ± 0.6 60.0 ± 9.2 165.0 ± 6.0 22.1 ± 3.4 858 ± 108  n = 124 All values are mean ± SD. The percent of girls having experienced their first menstruations was: 0, 1.8, and 25.5% at the age of 8.9, 10.0, and 12.4 years,

respectively. All participants were menstruating at the visit when their mean age was 16.4. ± 0.5 year BMI body mass index, FN Femoral neck, aBMD areal bone mineral density, NA not available Table 2 Regressions between Z-scores of body mass index (BMI) and menarcheal age (A) and between delta Z-scores of BMI and menarcheal age (B)   N β P 95% CI for R 2 Lower Upper A) Age (year/s) Birth 115 −0.070 0.468 −0.259 0.120 0.01 1 96 −0.026 0.804 −0.237 0.184 0.01 7.9 124 −0.336 0.000 −0.505 −0.167 0.11 8.9 123 −0.337 0.000 −0.506 −0.169 0.11 10.0 114 −0.341 0.000 −0.515 −0.166 0.12 12.4 105 −0.455 0.000 −0.644 −0.265 0.18 16.4 113 −0.327 0.001 −0.510 −0.137 0.10 (0.001)a 20.4 124 −0.208 0.020 −0.383 −0.033 0.04 (0.018)a B) Delta age (years) Birth to 1 96 −0.048 0.734 −0.328 0.232 0.01 1 to 7.9 96 −0.245 0.058 −0.499 0.009 0.04 1 to 8.9 96 −0.260 0.050 −0.519 0.000 0.04 1 to 10.0 92 −0.356 0.010 −0.624 −0.088 0.07 1 to 12.4 88 −0.417 0.006 −0.710 −0.123 0.08 1 to 16.4 92 −0.199 0.268 −0.553 0.156 0.01 (0.