Characteristics of the female study participants by baseline age group and smoking categories.

The Hordaland Health StudyaAbbreviations: BMD, bone mineral density; BMI, body mass index.aValues are given as mean (standard deviation (SD)) for continuous variables and number (%) for categorical variables.bNever smoking, plasma cotinine levels cotinine levels cNumber of participants with data on femoral neck BMD, body soft tissue composition and plasma cotinine.dP-value for trend across smoking categories.eHip fractures from inclusion in 1998-2000 until December 31st, 2009.Total numbers may vary between variables due to varying numbers of missing data.