title: Exercise, smoking, and calcium intake during adolescence and early adulthood as determinants of peak bone mass. Cardiovascular Risk in Young Finns Study Group.
abstract: OBJECTIVE
  To evaluate the contribution to peak bone mass of exercise, smoking, and calcium intake in adolescents and young adults.
  
  
  METHODS
  Prospective cohort study with end point measurement (bone mineral density) after 11 years' follow up for lifestyle.
  
  
  METHODS
  Five university hospital clinics.
  
  
  METHODS
  264 (153 females, 111 males) subjects aged 9 to 18 years at the beginning of the follow up and 20 to 29 years at the time of measurement of bone mineral density.
  
  
  METHODS
  Bone mineral density of lumbar spine and femoral neck by dual energy x ray absorptiometry; measures of physical activity and smoking and estimates of calcium intake repeated three times during follow up.
  
  
  RESULTS
  In the groups with the lowest and highest levels of exercise the femoral bone mineral densities (adjusted for age and weight) were 0.918 and 0.988 g/cm2 for women (P = 0.015, analysis of covariance) and 0.943 and 1.042 g/cm2 for men (P = 0.005), respectively; at the lumbar spine the respective values were 1.045 and 1.131 (P = 0.005) for men. In men the femoral bone mineral densities (adjusted for age, weight, and exercise) were 1.022 and 0.923 g/cm2 for the groups with the lowest and highest values of smoking index (P = 0.054, analysis of covariance). In women the adjusted femoral bone mineral density increased by 4.7% together with increasing calcium intake (P = 0.089, analysis of covariance). In multiple regression analysis on bone mineral density of the femoral neck, weight, exercise, age, and smoking were independent predictors for men; with weight, exercise, and age for women. These predictors together explained 38% of the variance in bone mineral density in women and 46% in men. At the lumbar spine, weight, smoking, and exercise were predictors for men; and only weight for women.
  
  
  CONCLUSIONS
  Regular exercise and not smoking is important in achieving maximal peak bone mass in adolescents and young adults.
authors.affiliation: Department of Medicine, Helsinki University Central Hospital, Finland.
authors.forename: M J
authors.initials: MJ
authors.lastname: Välimäki
authors.forename: M
authors.initials: M
authors.lastname: Kärkkäinen
authors.forename: C
authors.initials: C
authors.lastname: Lamberg-Allardt
authors.forename: K
authors.initials: K
authors.lastname: Laitinen
authors.forename: E
authors.initials: E
authors.lastname: Alhava
authors.forename: J
authors.initials: J
authors.lastname: Heikkinen
authors.forename: O
authors.initials: O
authors.lastname: Impivaara
authors.forename: P
authors.initials: P
authors.lastname: Mäkelä
authors.forename: J
authors.initials: J
authors.lastname: Palmgren
authors.forename: R
authors.initials: R
authors.lastname: Seppänen
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D001835:Body Weight; D015519:Bone Density; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000378:metabolism; D002648:Child; D015331:Cohort Studies; D015444:Exercise; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D005500:Follow-Up Studies; D006801:Humans; D008019:Life Style; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D011446:Prospective Studies; D012044:Regression Analysis; D012737:Sex Factors; D012907:Smoking / Q000378:metabolism*
chemical_list: D002136:Calcium, Dietary