Higher parity is associated with increased risk of Type 2 diabetes mellitus in women: A linear dose-response meta-analysis of cohort studies.
The goal of this study is to investigate the association between higher parity and the risk of occurrence of type 2 diabetes mellitus (T2DM) in women and to quantify the potential dose-response relation.



We searched MEDLINE, and EMBASE electronic databases for related cohort studies up to March 10th, 2016. Summary rate ratios (RRs) and 95% confidence intervals (CIs) for T2DM with at least 3 categories of exposure were eligible. A random-effects dose-response analysis procedure was used to study the relations between them.



After screening a total of 13,647 published studies, only 7 cohort studies (9,394 incident cases and 286,840 female participants) were found to be eligible for this meta-analysis. In the category analysis, the pooled RR for the highest number of parity vs. the lowest one was 1.42 (95% CI: 1.17-1.72, I2=71.5%, Pheterogeneity=0.002, Power=0.99). In the dose-response analysis, a noticeable linear dose-risk relation was found between parity and T2DM (Pfor nonlinearity test=0.942). For every live birth increase in parity, the combined RR was 1.06 (95% CI: 1.02-1.09, I2=84.3%, Pheterogeneity=0.003, Power=0.99). Subgroup and sensitivity analyses yielded similar results. No publication bias was found in the results.



This meta-analysis suggests that higher parity and the risk of T2DM show a linear relationship in women.
Department of Hepatobiliary Surgery, Renmin Hospital, Hubei University of Medicine, Hubei 442000, China. Electronic address: guop_doc@163.com.
Peng
P
Guo
Department of Science and Education, The First People's Hospital of Changde City, Hunan, 415003, China.
Quan
Q
Zhou
Department of Joint Surgery, The Third Affiliated Hospital of Zunyi Medical University, Zunyi 563000, China.
Lei
L
Ren
Department of Spinal Surgery, The Third Affiliated Hospital of Zunyi Medical University, Zunyi 563000, China.
Yu
Y
Chen
Department of Intensive Care Unit, Taihe Hospital, Hubei University of Medicine, Hubei, 442000, China. Electronic address: dfhy520115@163.com.
Yue
Y
Hui
D000328:Adult; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010298:Parity / Q000502:physiology*; D011247:Pregnancy; D017584:Reproductive History; D012307:Risk Factors
Cohort studies; Dose–response; Meta-analysis; Parity; Type 2 diabetes mellitus