The total body less head (TBLH) region was used to represent the child’s total bone mass, with the head excluded as bone development here is different from the rest of the skeleton and less likely to be influenced by environmental factors. In contrast to the overall skeleton which primarily comprises cortical SHP099 mouse bone, the spine subregion which was also analysed has a relatively high proportion of trabecular bone. One operator reanalysed the scans to check and adjust automated placement of body regions; in the case of the spinal region, the upper border comprises the

cervicothoracic junction, the lower border the lumbosacral junction, and the lateral borders the bone/soft tissue interface. Since curvature in the image of the spine leads to contamination of the spinal region with the ribs, only images with minor or no curvature are included in the analysis selleck chemicals llc of spinal outcomes. Measurements for TBLH and spine BMC, bone area (BA) and areal BMD were subsequently calculated. For both regions, area-adjusted BMC (ABMC)

was also derived as a measure of volumetric BMD by using linear regression to adjust BMC for BA and adding the residuals to the mean BMC for the region. The coefficient of variation for TBLH BMD was 0.84% based on 122 pairs of scans repeated on the same day. At the same time as the DXA scan, the child’s standing height (without shoes) was measured using a Harpenden Stadiometer (Holtain Ltd., UK) and weight (unshod and in light clothing) was measured using a Tanita Body Fat Selleckchem DAPT Analyzer (model TBF 305, Tanita UK Limited, UK). Maternal and paternal smoking At 18 weeks’ gestation, the mothers were sent a postal questionnaire which asked how many times per day they had smoked in the first trimester and in the last 2 weeks, representing smoking during the second trimester. At 32 weeks’ gestation,

another postal questionnaire asked how many cigarettes per day the woman was currently smoking, representing smoking during the third trimester. Variables describing smoking in any trimester and smoking in all trimesters were derived from these responses, with one or more cigarettes smoked per day considered as smoking BCKDHA regularly. A questionnaire completed by the mother’s partner at 18 weeks’ gestation asked if he had smoked regularly at any time in the last 9 months. The mother was also asked if her partner smoked in her 18-week questionnaire, and a positive response from either the partner or the mother was assumed sufficient to indicate that the partner smoked regularly during the pregnancy. Other variables Maternal and paternal height, weight and highest educational qualifications, household social class, father’s age and the mother’s parity were obtained from questionnaires administered during pregnancy. Household social class was defined from the highest parental occupation, on a scale from I to V, with I indicating a professional/managerial role and V being unskilled manual.