Dataset Information

Pregnancy duration and endometrial cancer risk: nationwide cohort study.

ABSTRACT:

Objective

To explore the association between pregnancy duration and risk of endometrial cancer.

Design

Nationwide register based cohort study.

Setting

Denmark.

Participants

All Danish women born from 1935 to 2002.

Main outcome measures

Relative risk (incidence rate ratio) of endometrial cancer by pregnancy number, type, and duration, estimated using log-linear Poisson regression.

Results

Among 2?311?332 Danish women with 3?947?650 pregnancies, 6743 women developed endometrial cancer during 57?347?622 person years of follow-up. After adjustment for age, period, and socioeconomic factors, a first pregnancy was associated with a noticeably reduced risk of endometrial cancer, whether it ended in induced abortion (adjusted relative risk 0.53 (95% confidence interval 0.45 to 0.64) or childbirth (0.66, 0.61 to 0.72). Each subsequent pregnancy was associated with an additional reduction in risk, whether it ended in induced abortion (0.81, 0.77 to 0.86) or childbirth (0.86, 0.84 to 0.89). Duration of pregnancy, age at pregnancy, spontaneous abortions, obesity, maternal birth cohort, fecundity, and socioeconomic factors did not modify the results.

Conclusions

The risk of endometrial cancer is reduced regardless of whether a pregnancy ends shortly after conception or at 40 weeks of gestation. This reduction in risk could be explained by a biological process occurring within the first weeks of pregnancy, as pregnancies ending in induced abortions were associated with similar reductions in risk as pregnancies ending in childbirth.

SUBMITTER: Husby A

PROVIDER: S-EPMC6693051 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Pregnancy duration and endometrial cancer risk: nationwide cohort study.

Husby Anders A Wohlfahrt Jan J Melbye Mads M

BMJ (Clinical research ed.) 20190814

<h4>Objective</h4>To explore the association between pregnancy duration and risk of endometrial cancer.<h4>Design</h4>Nationwide register based cohort study.<h4>Setting</h4>Denmark.<h4>Participants</h4>All Danish women born from 1935 to 2002.<h4>Main outcome measures</h4>Relative risk (incidence rate ratio) of endometrial cancer by pregnancy number, type, and duration, estimated using log-linear Poisson regression.<h4>Results</h4>Among 2 311 332 Danish women with 3 947 650 pregnancies, 6743 wome ...[more]

PMID: 31412996

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Project description:BackgroundNitrate contamination is seen in drinking water worldwide. Nitrate may pass the placental barrier. Despite suggestive evidence of fetal harm, the potential association between nitrate exposure from drinking water and pregnancy loss remains to be studied. We aimed to investigate if nitrate in drinking water was associated with the risk of pregnancy loss.MethodsWe conducted a nationwide cohort study of 100,410 pregnancies (enrolled around gestational week 11) in the Danish National Birth Cohort (DNBC) during 1996-2002. Spontaneous pregnancy losses before gestational week 22 were ascertained from the Danish National Patient Registry and DNBC pregnancy interviews. Using the national drinking water quality-monitoring database Jupiter, we estimated the individual and time-specific nitrate exposure by linking geocoded maternal residential addresses with water supply areas. The nitrate exposure was analyzed in spline models using a log-transformed continuous level or classified into five categories. We used Cox proportional hazards models to estimate associations between nitrate and pregnancy loss and used gestational age (days) as the time scale, adjusting for demographic, health, and lifestyle variables.ResultsNo consistent associations were found when investigating the exposure as a categorical variable and null findings were also found in trimester specific analyses. In the spline model using the continuous exposure variable, a modestly increased hazard of pregnancy loss was observed for the first trimester at nitrate exposures between 1 and 10 mg/L, with the highest. adjusted hazard ratio at 5 mg/L of nitrate of 1.16 (95% CI: 1.01, 1.34). This trend was attenuated in the higher exposure ranges.ConclusionNo association was seen between drinking water nitrate and the risk of pregnancy loss when investigating the exposure as a categorical variable. When we modelled the exposure as a continuous variable, a dose-dependent association was found between drinking water nitrate exposure in the first trimester and the risk of pregnancy loss. Very early pregnancy losses were not considered in this study, and whether survival bias influenced the results should be further explored.

Dataset Information

Pregnancy duration and endometrial cancer risk: nationwide cohort study.

Objective

Design

Setting

Participants

Main outcome measures

Results

Conclusions

Publications

Pregnancy duration and endometrial cancer risk: nationwide cohort study.

Similar Datasets

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