Effect of high parity on the occurrence of prediabetes: a cohort study.
OBJECTIVE
To assess the effect of parity on the occurrence of prediabetes defined as an abnormal fasting plasma glucose (5.6-6.9 mmol/l), an abnormal 2-hour oral glucose tolerance test (7.7-11.1 mmol/l), or both, before 12 weeks gestation or at least 6 weeks after delivery.


METHODS
Retrospective cohort study.


METHODS
Nested on a community trial Delaying the Development of Diabetes Mellitus type 2 (AMAL study) in Oman.


METHODS
532 women with a total of 3,196 pregnancies.


METHODS
We conducted sets of Cox proportional hazard regression analyses: crude, age-adjusted and full models which adjusted for maternal age, education, family income and year of delivery.


METHODS
Hazard ratio (HR) of the effect of parity on prediabetes.


RESULTS
We enumerated 258 cases of prediabetes over 8,529 person-years of follow up. In the crude model, high parity (> or =5) pregnancies carried a higher risk of prediabetes than low parity (<5) pregnancies (HR = 3.72; 95% CI = 2.80, 4.91), and the prediabetes incidence rate increased in a dose-response fashion over multiple categories of parity. In age-only models, the association attenuated with control of the confounding effect of maternal age (HR = 1.05; 95% CI = 0.76, 1.45). Adjusting for other confounders in the full models yielded similar results to those adjusted for maternal age only.


CONCLUSIONS
The apparent effect of parity on the occurrence of prediabetes is attributable to the confounding effect of maternal age rather than to high parity.
Al-Farsi
Yahya M
YM
Department of Family Medicine and Public Health, Sultan Qaboos University, Oman. ymfarsi@squ.edu.om
Brooks
Daniel R
DR
Werler
Martha M
MM
Cabral
Howard J
HJ
Al-Shafei
Mohammed A
MA
Wallenburg
Henk C
HC
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D009850:Oman / Q000453:epidemiology; D010298:Parity; D011236:Prediabetic State / Q000453:epidemiology*; D011247:Pregnancy; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment