Background
Type 2 diabetes (T2DM) has reached epidemic proportions. Women with
gestational diabetes mellitus (GDM) are at high risk for T2DM after
pregnancy. Adherence to healthful dietary patterns has been inversely
associated with T2DM in the general population; however whether these
dietary patterns are associated with progression to T2DM among a susceptible
population is unknown.
Methods
4,413 participants from the Nurses’ Health Study II cohort
with prior GDM were followed from 1991–2005. The alternate
Mediterranean Diet (aMED), Dietary Approaches to Stop Hypertension (DASH),
and alternate Healthy Eating Index (aHEI) dietary pattern adherence scores
were derived from post-GDM validated food-frequency questionnaire, with
cumulative average updating every 4 years. Multivariable Cox proportional
hazards models estimated the relative risk (HR) and 95% confidence
intervals [95% CI].
Results
491 cases of incident T2DM were observed over 52,743 person-years.
All three patterns were inversely associated with T2DM risk adjusting for
age, total calories, age at first birth, parity, ethnicity, parental
diabetes, oral contraceptive use, menopause, and smoking. Comparing
participants with highest adherence (quartile 4) versus lowest (quartile 1),
the aMED pattern was associated with 40% lower risk of T2DM
(HR=0.60 [95% CI: 0.44, 0.82]
p-trend=0.0019), DASH with 46% lower risk (HR=0.54
[95% CI: 0.39, 0.73] p-trend=0.0002), and
aHEI with 57% lower risk (HR=0.43 [95% CI:
0.31, 0.59] p-trend<0.0001). Adjustment for body mass index
(BMI) moderately attenuated these findings.
Conclusions
Adherence to healthful dietary patterns is associated with lower T2DM
risk among women with a history of GDM. The inverse associations were partly
mediated by BMI.