The overall aim of this study is to examine the relationship between active and passive smoking and cardiometabolic risk factors (blood pressure, fasting glucose, insulin, lipids and inflammatory markers) in adolescence. Methods

The exposure variables are (a) serum cotinine levels in the ALSPAC YP (young person) assessed at teen-focus 3 (TF3; age 15-16 years); (b) self-reported smoking of YP at TF3; (c) self-report of the parents of the YP from their most recent (relative to TF3) questionnaire; we will also consider YP adiposity (BMI, waist and DXA fat mass) as an exposure for objective d and examine whether it interacts with smoking/cotinine in their associations with cardiometabolic outcomes or whether they combine independently

The outcome variables are systolic and diastolic blood pressure, fasting glucose, insulin, lipids and CRP in the YP assessed at TF3

We will consider the following as potential confounding factors: YP age, YP gender, YP pubertal status, maternal age at birth, maternal parity, head of household (parental) occupational social class, maternal and paternal education, ethnicity. YP adiposity will also be considered a potential confounding factor for objectives a-c and e but we will decide just how to model this after exploring the joint associations of this and smoking/cotinine with outocmes