The association of a high drive for thinness with energy deficiency and severe menstrual disturbances: confirmation in a large population of exercising women

Journal Title (Medline/Pubmed accepted abbreviation): Int J Sport Nutr Exerc Metab Metab.
Year: 2011
Volume: 21
Number: 4
Page numbers: 280-290

Summary of background and research design:

Background: The female athlete triad syndrome exhibits as low-energy availability, functional hypothalamic amenorrhea, and low bone-mineral density. A high drive-for-thinness (DT) may be a key factor in the development of the triad syndrome. Evidence supports a strong correlation between DT, subclinical eating disorders, and amenorrhea in exercising women. A high DT score may indicate underlying energy deficiencies as measured by resting energy expenditure (REE), but confirmation is needed.

Hypothesis: Exercising women with a high DT would exhibit an energy deficiency and a greater prevalence of severe menstrual disturbances.

Subjects: One hundred and seventeen healthy, adult women who exercised (≥ 2 hr/wk; maximal oxygen uptake [VO2max] ≥ 40 mL/kg/min) participated in this study. Baseline characteristics were similar between high and normal DT groups: mean age, ~23 years, height, ~165 cm, body mass index, ~21 kg/m2, and body fat, ~26 %.

Experimental design: Cross-sectional

Treatments and protocol: Exercising women were stratified by their DT scores as high (≥ 7) or normal. Each woman was monitored for 1 menstrual cycle (up to 90 days) or 28 days (self-reported). Once during the study, REE (including tri-iodothyronine [TT3] levels), DT score, and VO2max were evaluated. Dietary intake was assessed twice from 3-day food diaries. Exercise volume was assessed from 2 separate logs of 7-day intervals.

Summary of research findings:
  • More cases of energy deficiency were reported in women with high DT vs normal DT (P = .024).
    • Both REE and REE:pREE (predicted) were lower in women with high DT (P < .001 for both).
    • Daily dietary intake was also lower (P = .014)
    • DT was negatively correlated with REE parameters (P ≤ .041 for all)
    • Log TT3 concentration was positively correlated with both REE (P = .023) and REE:pREE (P = .030)
  • Women with high DT had more cases of severe menstrual disturbances (amenorrhea or oligomenorrhea) than did normal DT women (73.9% vs 38.0%; P = .002).
    • This was driven by amenorrhea and not oligomenorrhea.
    • DT was inversely related to number of menses reported in previous 3 months (P = .004).
  • DT scores were positively correlated with dietary cognitive restraint and perfectionism (P < .001 for both).

Interpretation of findings/Key practice applications:

These results confirm earlier reports correlating DT with energy deficiency in exercising women. Additionally, DT was associated with suppressed reproductive function. However, energy intake and physical activity were self-reported and are susceptible to underreporting. Therefore, this method may not be sensitive to difference in energy expenditure, and differences from restrictive eating and energy expenditure cannot be separated in this study. Nevertheless, DT scores provide a useful assessment for energy and menstrual status in large groups of exercising women.

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