Effects of Gender, Alcohol, Smoking, and Dairy Consumption on Bone Mass in Wisconsin Adolescents

Introduction: Failure to attain peak bone mass during adolescence may be an important contributor to the development of osteoporosis.

Methods: This prospective, descriptive study evaluated the relationship between osteoporosis risk factors and attainment of bone mass in 239 Wisconsin high school students. Students completed an annual risk assessment questionnaire that included questions about dairy intake, alcohol use, and smoking. Heel bone mineral density (BMD) was measured in the 9th grade (year 1) and 12th grade (year 4).

Results: A total of 109 students were included in the final analysis of a covariance model used to predict year 4 BMD. The model included separate year 1 BMD slope and intercept terms for males and females and indicator variables for adequate dairy intake and combined alcohol habits or smoking habits (overall P<0.001, multiple r2=0.871). The predicted year 4 BMD for females was 0.07 g/cm2 plus 85.6% of their year 1 BMD. For males, predicted year 4 BMD was 0.008 g/cm2 plus 110% of their year 1 BMD. Self-reported dairy intake of > or = 4 servings per day was associated with a 0.032 g/cm2 increase in BMD, while self-reported smoking or alcohol use was associated with a decrease in BMD of 0.028 g/cm2.

Conclusions: Alcohol or smoking had a significant negative effect on bone density, whereas adequate dairy intake (>4 servings per day) had a favorable effect in Wisconsin adolescents. Sex differences in bone density growth were clearly identified, with males tending to gain BMD and females tending to lose BMD by year 4.