Coffee and caffeine consumption in relation to sex hormone-binding globulin and risk of type 2 diabetes in postmenopausal women

Diabetes. 2011 Jan;60(1):269-75. doi: 10.2337/db10-1193. Epub 2010 Oct 28.


Objective: Coffee consumption has been inversely associated with type 2 diabetes risk, but its mechanisms are largely unknown. We aimed to examine whether plasma levels of sex hormones and sex hormone-binding globulin (SHBG) may account for the inverse association between coffee consumption and type 2 diabetes risk.

Research design and methods: We conducted a case-control study nested in the prospective Women's Health Study (WHS). During a median follow-up of 10 years, 359 postmenopausal women with newly diagnosed type 2 diabetes were matched with 359 control subjects by age, race, duration of follow-up, and time of blood draw.

Results: Caffeinated coffee was positively associated with SHBG but not with sex hormones. Multivariable-adjusted geometric mean levels of SHBG were 26.6 nmol/l among women consuming ≥4 cups/day of caffeinated coffee and 23.0 nmol/l among nondrinkers (P for trend = 0.01). In contrast, neither decaffeinated coffee nor tea was associated with SHBG or sex hormones. The multivariable-adjusted odds ratio (OR) of type 2 diabetes for women consuming ≥4 cups/day of caffeinated coffee compared with nondrinkers was 0.47 (95% CI 0.23-0.94; P for trend = 0.047). The association was largely attenuated after further adjusting for SHBG (OR 0.71 [95% CI 0.31-1.61]; P for trend = 0.47). In addition, carriers of rs6259 minor allele and noncarriers of rs6257 minor allele of SHBG gene consuming ≥2 cups/day of caffeinated coffee had lower risk of type 2 diabetes in directions corresponding to their associated SHBG.

Conclusions: Our findings suggest that SHBG may account for the inverse association between coffee consumption and type 2 diabetes risk among postmenopausal women.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Beverages
  • Caffeine / adverse effects*
  • Coffee / adverse effects*
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Diet
  • Double-Blind Method
  • Feeding Behavior
  • Female
  • Gonadal Steroid Hormones / blood
  • Humans
  • Middle Aged
  • Multivariate Analysis
  • Odds Ratio
  • Postmenopause*
  • Sex Hormone-Binding Globulin / drug effects
  • Sex Hormone-Binding Globulin / metabolism*
  • Surveys and Questionnaires


  • Coffee
  • Gonadal Steroid Hormones
  • Sex Hormone-Binding Globulin
  • Caffeine