Age and multivariable adjusted means of mammographic density measures by physical activity.

*Percent density and dense area were square-root transformed for analysis and the values shown are on a back-transformed scale. † In ever smokers only. Model 1: adjusted for age at mammography Model 2: adjusted for age at mammography, BMI, age at menarche, parity and age at first birth (nulliparous, 1 child age at first birth <25 years, 1 child age at first birth ≥25 years, 2 children age at first birth <25 years, 2 children age at first birth ≥25 years, ≥3 children age at first birth <25 years, ≥3 children age at first birth ≥25 years), age at menopause, OC use (never, ever), HRT use (never, former, current), smoking (never, former, current), alcohol intake (non-drinker, 0,1–4,9 g/day, 5.0–9.9 g/day, ≥10 g/day), and physical activity recent years (never, less than 1 hr per week, 1–2 hrs per week, >2 hrs per week).