title: Effect of a 12-month randomized clinical trial of exercise on serum prolactin concentrations in postmenopausal women.
abstract: Prolactin is associated with an increased risk of postmenopausal breast cancer; however, few modifiable factors are known to reduce prolactin concentrations. Therefore, we examined the effect of a 12-month moderate-intensity exercise intervention on serum prolactin concentrations as a secondary end point (primary end points were estrogens and androgens). We randomly assigned 173 postmenopausal women who were sedentary, overweight (body mass index >24 kg/m(2), body fat >33%), ages 50 to 75 years, and not using hormone therapy to an exercise intervention or stretching control group. The intervention was facility- and home-based (45 min, 5 days/wk moderate-intensity sports/recreational exercise). One hundred and seventy (98%) women completed the study. Prolactin concentrations were similar at baseline (P = 0.25, geometric mean exercisers = 6.9 and controls = 7.5 ng/mL). Overall, the intervention was not associated with changes in prolactin concentrations between exercisers and controls at 3 months (P = 0.46) or 12 months (P = 0.29). The intervention effect did not vary by baseline age, body mass index, parity, or change in percent body fat during the intervention. Among exercisers, there was a significant difference in prolactin concentrations by change in fitness (VO(2)max) between baseline and 12 months. Exercisers whose VO(2)max changed by <5% had a 5% increase in prolactin concentrations, whereas those who increased their VO(2)max by 5% to 15% and >15% had a 11% (P = 0.03) and 7% (P = 0.01) decrease in prolactin concentrations, respectively. Although the exercise intervention had little effect on prolactin concentrations overall, increasing physical fitness was associated with reduced prolactin concentrations among postmenopausal women.
authors.affiliation: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Shelley S
authors.initials: SS
authors.lastname: Tworoger
authors.forename: Bess
authors.initials: B
authors.lastname: Sorensen
authors.forename: Jessica
authors.initials: J
authors.lastname: Chubak
authors.forename: Melinda
authors.initials: M
authors.lastname: Irwin
authors.forename: Frank Z
authors.initials: FZ
authors.lastname: Stanczyk
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: Ulrich
authors.forename: John
authors.initials: J
authors.lastname: Potter
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000517:prevention & control*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D050177:Overweight; D017698:Postmenopause / Q000097:blood / Q000502:physiology*; D011388:Prolactin / Q000097:blood*
chemical_list: D011388:Prolactin