Pregnancy history and risk of premenopausal breast cancer—a nested case-control study

Hajiebrahimi, Mohammadhossein; Cnattingius, Sven; Lambe, Mats; Bahmanyar, Shahram

doi:10.1093/ije/dyv293

Cited by 15 publications

(16 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The literature on breast cancer risk in women with a history of preeclampsia is inconsistent. Some studies have reported an inverse association, one a positive association and others, including meta‐analyses, reported no association . Only two studies, both of case–control design, investigated the association between preeclampsia history and breast cancer by menopausal status, with one reporting a decreased risk of postmenopausal but not premenopausal breast cancer and the other no association in either group, contrary to our findings of a reduced risk of premenopausal but not postmenopausal breast cancer.…”

Section: Discussioncontrasting

confidence: 99%

“…5,6 It has been hypothesised that preeclampsia might therefore be associated with a decreased risk of maternal breast cancer. 7 Evidence from previous studies has been inconsistent, however, with studies reporting negative, [7][8][9][10][11] positive 12 or no [13][14][15][16][17] association with breast cancer risk. Few studies have been of prospective design and the studies have often not been able to adjust for potential confounders.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Breast cancer risk in relation to history of preeclampsia and hyperemesis gravidarum: Prospective analysis in the Generations Study

Wright

Schoemaker

Jones

et al. 2018

Intl Journal of Cancer

View full text Add to dashboard Cite

Preeclampsia and hyperemesis gravidarum are pregnancy complications associated with altered sex hormone levels. Previous studies suggest preeclampsia may be associated with a decreased risk of subsequent breast cancer and hyperemesis with an increased risk, but the evidence remains unclear. We used data from the Generations Study, a large prospective study of women in the United Kingdom, to estimate relative risks of breast cancer in relation to a history of preeclampsia and hyperemesis using Cox regression adjusting for known breast cancer risk factors. During 7.5 years average follow‐up of 82,053 parous women, 1,969 were diagnosed with invasive or in situ breast cancer. Women who had experienced preeclampsia during pregnancy had a significantly decreased risk of premenopausal breast cancer (hazard ratio (HR) =0.67, 95% confidence interval (CI): 0.49–0.90) and of HER2‐enriched tumours (HR = 0.33, 95% CI: 0.12–0.91), but there was no association with overall (HR = 0.90, 95% CI: 0.80–1.02) or postmenopausal (HR = 0.97, 95% CI: 0.85–1.12) breast cancer risk. Risk reductions among premenopausal women were strongest within 20 years since the last pregnancy with preeclampsia. Hyperemesis was associated with a significantly increased risk of HER2‐enriched tumours (HR = 1.76, 95% CI: 1.07–2.87), but not with other intrinsic subtypes or breast cancer risk overall. These results provide evidence that preeclampsia is associated with a decreased risk of premenopausal and HER2‐enriched breast cancer and that hyperemesis, although not associated with breast cancer risk overall, may be associated with raised risk of HER2‐enriched tumours.

show abstract

Section: Discussioncontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Breast cancer risk in relation to history of preeclampsia and hyperemesis gravidarum: Prospective analysis in the Generations Study

Wright

Schoemaker

Jones

et al. 2018

Intl Journal of Cancer

View full text Add to dashboard Cite

show abstract

“…In theory, late-pregnancy stimuli that transform the breast tissue to a stage represented by a lowered breast cancer risk could originate from both the mother and the fetus. However, findings by us and others provide little evidence for a fetal involvement since infant sex 23 , infant absolute birthweight 10 , 24 or, as we show, fetal growth restriction and vital status of the infant at birth do not influence the long-term breast cancer risk.…”

Section: Discussioncontrasting

confidence: 93%

Pregnancy duration and breast cancer risk

et al. 2018

View full text Add to dashboard Cite

Full-term pregnancies reduce a woman’s long-term breast cancer risk, while abortions have been shown to have no effect. The precise minimal duration of pregnancy necessary to lower a woman’s breast cancer risk is, however, unknown. Here we provide evidence which point to the protective effect of pregnancy on breast cancer risk arising precisely at the 34th pregnancy week. Using a cohort of 2.3 million Danish women, we found the reduction in breast cancer risk was not observed for pregnancies lasting 33 weeks or less, but restricted to those pregnancies lasting 34 weeks or longer. We further found that parity, socioeconomic status, and vital status of the child at birth did not explain the association, and also replicated our finding in data from 1.6 million women in Norway. We suggest that a distinct biological effect introduced around week 34 of pregnancy holds the key to understand pregnancy-associated breast cancer protection.

show abstract

“…[15][16][17] This trend among premenopausal women may reflect a change in risk factors, including later age at first childbirth, increased oral contraceptive use and earlier age at menarche. [18][19][20][21][22][23][24][25][26][27][28][29] A similar trend was noted for colorectal and pancreatic cancer, which has also been seen in the US. 30,31 These findings solidify the need for public health measures and interventions that address weight management and are aimed at younger adults.…”

Section: Discussionmentioning

confidence: 55%

Age-standardized cancer-incidence trends in Canada, 1971–2015

Brenner

Ruan

Shaw

et al. 2019

CMAJ

View full text Add to dashboard Cite

xamination of historical data in Canada suggests that overall age-standardized incidence rates of cancer have decreased in males, but have increased in females. 1 Among both males and females between 1992 and 2013, the annual percent change (APC) in age-standardized incidence rates varied considerably among cancer sites, with the largest proportional increases seen in thyroid and liver cancers, and the largest decreases seen in stomach and laryngeal cancers. 1 However, analysis of age-standardized overall cancer rates may mask important epidemiologic trends for a given cancer site. For example, while overall rates of colorectal cancer are decreasing in Canada, we have previously shown that incidence is increasing substantially among adults younger than 50 years of age. 2 This discrepancy highlights the importance of examining the long-term trends in age-standardized incidence by individual cancer sites, which may be missed in overall trends. Age-standardized trends may provide insights that are of clinical or epidemiologic value, such as how previous primaryand secondary-prevention interventions affected the health of a population. Analysis by birth cohort can also help to inform hypotheses about potential early-life risk factors that have changed over generations. Finally, understanding cancerincidence trends specific to age and birth cohort can help guide future health-resource planning, as they may suggest health care needs of subpopulations. Although trends in cancer incidence have been well characterized in Canada for all ages combined, age-and birth cohort-specific trends have not been investigated for most cancer sites. In this study, we examined age-and birth cohort-specific incidence trends in Canada between 1971 and 2015 for 16 major cancer sites and all cancers combined.

show abstract

Pregnancy history and risk of premenopausal breast cancer—a nested case-control study

Abstract: The divergent results with regard to parity and PBC risk when using sister and population controls suggest that the influence of childbearing may be modified by genotype. Selection bias when using different control groups must also be considered.

Cited by 15 publications

References 45 publications

Breast cancer risk in relation to history of preeclampsia and hyperemesis gravidarum: Prospective analysis in the Generations Study

Breast cancer risk in relation to history of preeclampsia and hyperemesis gravidarum: Prospective analysis in the Generations Study

Pregnancy duration and breast cancer risk

Age-standardized cancer-incidence trends in Canada, 1971–2015

Contact Info

Product

Resources

About