Gestational diabetes and the risk of breast cancer among women in the Jerusalem Perinatal Study

Risk of Breast Cancer After Diabetes in Pregnancy: A Population-based Cohort Study

OBJECTIVES

Diabetes is associated with an increased risk of several cancers, including postmenopausal breast cancer. The evidence for higher breast cancer risk after diabetes in pregnancy is conflicting. We compared the incidence of breast and other cancers between pregnant women with and without diabetes.

METHODS

This work was a propensity-matched, retrospective cohort study using population-based health-care databases from Ontario, Canada. Those deliveries with gestational diabetes mellitus (GDM) and pregestational diabetes mellitus (pregestational DM) were identified and matched to deliveries without diabetes mellitus (non-DM). Deliveries from each diabetes cohort were matched 1:2 on age, parity, year of delivery, and propensity score to non-DM deliveries. Matched subjects were followed from delivery for incidence of breast cancer as a primary outcome, and other site-specific cancers as secondary outcomes. We performed Cox proportional hazards regression to compare rates of breast cancer between matched groups.

RESULTS

Over a median of 8 (interquartile range 4 to 13) years of follow-up, compared with non-DM deliveries, the incidence of breast cancer was significantly lower for GDM but similar for pregestational DM deliveries (hazard ratio [HR] 0.90, 95% confidence interval [CI] 0.82 to 0.98; and HR 0.92, 95% CI 0.80 to 1.07, respectively). GDM was associated with a significantly higher incidence of pancreatic and hepatocellular cancer, and pregestational DM was associated with a higher incidence of thyroid, hepatocellular, and endometrial cancers.

CONCLUSIONS

Diabetes in pregnancy does not have a higher short-term risk of subsequent breast cancer, but there may be a higher incidence of other cancers.

The Relationship Between Gestational Diabetes and the Risk of Cancer: A Systematic Review

Gestational diabetes mellitus (GDM) is one of the most common endocrine disorders to occur during pregnancy due to the increase in circulating human placental lactogen (hPL) and possible beta-cell sensitivity. While GDM can be managed either with diet and exercise or pharmacological interventions, it is associated with significant maternal and neonatal complications. Maternal complications include short- and long-term conditions such as pre-eclampsia, preterm birth, arrest of labor, future development of type 2 diabetes mellitus (T2DM), and cardiovascular disorders. Neonates can develop hypoglycemia and hypocalcemia and have a large gestational age (LGA). New research has also highlighted another possible long-term complication for both mothers and offspring, which is the development of cancer. Cancer has various types of progression, but most cause systemic symptoms leading to a reduced quality of life. Cancer can be terminal and can affect the majority of the population; thus, significant effort is being employed to try and reduce its occurrence. This systematic review was conducted with adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using PubMed, ScienceDirect, and ProQuest databases. Initially, 136,019 publications were identified. Through the screening process, a total of 27 publications were finalized within the scope of this paper. Most studies observing maternal cancer with a history of GDM found that there was an association between the increased risk of cancer and GDM. Specifically, these studies identified the association of GDM with breast, ovarian, cervical, and uterine cancer, as well as other non-reproductive organs such as the thyroid and pancreas. Cancer development in the offspring also presented an association with mothers who developed GDM. The most prevalent cancer evaluated was leukemia, and it was specifically associated with a maternal history of GDM. With the consistent rise in the incidence of cancer, any attempts to reduce its development are imperative to assess. While GDM is essentially a temporary condition that resolves following pregnancy in most patients, the possibility of contributing to future conditions years after its occurrence creates a sense of urgency and necessity to reduce the incidence of GDM. Researchers should be able to identify other unknown biomarkers that contribute to the development of cancer in mothers who experienced GDM as well as their infants.

Association of Gestational Diabetes With Subsequent Long-Term Risk of Mortality

Importance

Gestational diabetes has been associated with numerous chronic diseases. However, few studies have examined the association of gestational diabetes with long-term mortality risk.

Objective

To investigate the associations between gestational diabetes and long-term risks of total and cause-specific mortality.

Design, Setting, and Participants

This cohort study analyzed participants of the Nurses' Health Study II who were followed for 30 years (1989-2019). Participants included US female nurses aged 25 to 42 years who reported at least 1 pregnancy (≥6 months) at 18 years or older across their reproductive life span. Data were analyzed from May 1, 2022, to May 25, 2023.

Exposure

Gestational diabetes across the reproductive life span.

Main Outcomes and Measures

Hazard ratios (HRs with 95% CIs) for total and cause-specific mortality were estimated by Cox proportional hazards regression models.

Results

A total of 91 426 parous participants were included, with a mean (SD) age of 34.9 (4.7) years and a body mass index of 24.1 (4.7) at baseline. During a follow-up period of 2 609 753 person-years, 3937 deaths were documented, including 255 deaths from cardiovascular disease and 1397 from cancer. Participants with a history of gestational diabetes had a higher crude mortality rate than those without a history of gestational diabetes (1.74 vs 1.49 per 1000 person-years; absolute difference = 0.25 per 1000 person-years). The corresponding HR for total mortality was 1.28 (95% CI, 1.13-1.44), which did not materially change after additional adjustment for potential confounders and lifestyle factors during the reproductive life span (HR, 1.25; 95% CI, 1.11-1.41). The association persisted regardless of the subsequent development of type 2 diabetes and was more robust among participants who adopted less healthy lifestyles; experienced gestational diabetes in 2 or more pregnancies (HR, 1.48; 95% CI, 0.99-2.19); had gestational diabetes both in the initial and subsequent pregnancies (HR, 1.71; 95% CI, 1.11-2.63); and concurrently reported hypertensive disorders in pregnancy (HR, 1.80; 95% CI, 1.21-2.67), preterm birth (HR, 2.46; 95% CI, 1.66-3.64), or low birth weight (HR, 2.11; 95% CI, 1.21-3.68). Cause-specific mortality analyses revealed that gestational diabetes was directly associated with the risk of mortality due to cardiovascular disease (HR, 1.59; 95% CI, 1.03-2.47). Additionally, gestational diabetes was inversely associated with cancer mortality (HR, 0.76; 95% CI, 0.59-0.98); however, it was only evident among participants who later developed type 2 diabetes.

Conclusions and Relevance

Results of this cohort study suggest that participants who reported a history of gestational diabetes exhibited a small but elevated risk of subsequent mortality over 30 years. The findings emphasize the importance of considering gestational diabetes as a critical factor in later-life mortality risk.

Cardiovascular Disease-Associated MicroRNAs as Novel Biomarkers of First-Trimester Screening for Gestational Diabetes Mellitus in the Absence of Other Pregnancy-Related Complications

We assessed the diagnostic potential of cardiovascular disease-associated microRNAs for the early prediction of gestational diabetes mellitus (GDM) in singleton pregnancies of Caucasian descent in the absence of other pregnancy-related complications. Whole peripheral venous blood samples were collected within 10 to 13 weeks of gestation. This retrospective study involved all pregnancies diagnosed with only GDM (n = 121) and 80 normal term pregnancies selected with regard to equality of sample storage time. Gene expression of 29 microRNAs was assessed using real-time RT-PCR. Upregulation of 11 microRNAs (miR-1-3p, miR-20a-5p, miR-20b-5p, miR-23a-3p, miR-100-5p, miR-125b-5p, miR-126-3p, miR-181a-5p, miR-195-5p, miR-499a-5p, and miR-574-3p) was observed in pregnancies destinated to develop GDM. Combined screening of all 11 dysregulated microRNAs showed the highest accuracy for the early identification of pregnancies destinated to develop GDM. This screening identified 47.93% of GDM pregnancies at a 10.0% false positive rate (FPR). The predictive model for GDM based on aberrant microRNA expression profile was further improved via the implementation of clinical characteristics (maternal age and BMI at early stages of gestation and an infertility treatment by assisted reproductive technology). Following this, 69.17% of GDM pregnancies were identified at a 10.0% FPR. The effective prediction model specifically for severe GDM requiring administration of therapy involved using a combination of these three clinical characteristics and three microRNA biomarkers (miR-20a-5p, miR-20b-5p, and miR-195-5p). This model identified 78.95% of cases at a 10.0% FPR. The effective prediction model for GDM managed by diet only required the involvement of these three clinical characteristics and eight microRNA biomarkers (miR-1-3p, miR-20a-5p, miR-20b-5p, miR-100-5p, miR-125b-5p, miR-195-5p, miR-499a-5p, and miR-574-3p). With this, the model identified 50.50% of GDM pregnancies managed by diet only at a 10.0% FPR. When other clinical variables such as history of miscarriage, the presence of trombophilic gene mutations, positive first-trimester screening for preeclampsia and/or fetal growth restriction by the Fetal Medicine Foundation algorithm, and family history of diabetes mellitus in first-degree relatives were included in the GDM prediction model, the predictive power was further increased at a 10.0% FPR (72.50% GDM in total, 89.47% GDM requiring therapy, and 56.44% GDM managed by diet only). Cardiovascular disease-associated microRNAs represent promising early biomarkers to be implemented into routine first-trimester screening programs with a very good predictive potential for GDM.

Long-Term Follow-Up on Morbidity Among Women With a History of Gestational Diabetes Mellitus: A Systematic Review

BACKGROUND

Gestational diabetes mellitus (GDM) complicates up to 10% of pregnancies and is a well-known risk factor for type 2 diabetes mellitus (T2DM) and cardiovascular disease. Little is known about possible long-term risks of other diseases.

BACKGROUND

The aim was to review the literature for evidence of associations with morbidity other than T2DM and cardiovascular disease and with long-term mortality.

METHODS

A systematic review based on searches in Medline, Embase, and Cochrane Library until March 31, 2021, using a broad range of keywords. We extracted study characteristics and results on associations between GDM and disease occurrence at least 10 years postpartum, excluding studies on women with diabetes prior to pregnancy or only diabetes prior to outcome. The results are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Newcastle-Ottawa Scale was used to assess risk of bias.

RESULTS

We screened 3084 titles, 81 articles were assessed full-text, and 15 included in the review. The strongest evidence for an association was for kidney diseases, particularly in Black women. We found indication of an association with liver disease, possibly restricted to women with T2DM postpartum. The association between GDM and breast cancer had been studied extensively, but in most cases based on self-reported diagnosis and with conflicting results. Only sparse and inconsistent results were found for other cancers. No study on thyroid diseases was found, and no study reported on short-term or long-term mortality in women with a history of GDM.

CONCLUSION

Given the frequency of GDM, there is a need for better evidence on possible long-term health consequences, in particular, studies based on comprehensive records of diagnosis of GDM and long-term health outcomes.

Gestational diabetes and risk of breast cancer before age 55 years

BACKGROUND

The history of gestational diabetes mellitus (GDM) has been associated with breast cancer risk in some studies, particularly in young women, but results of cohort studies are conflicting.

METHODS

We pooled data from 257 290 young (age <55 years) women from five cohorts. We used multivariable Cox proportional-hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between GDM history and risk of breast cancer, overall and by oestrogen receptor (ER) status, before age 55 years, adjusted for established breast cancer risk factors.

RESULTS

Five percent of women reported a history of GDM and 6842 women reported an incident breast-cancer diagnosis (median follow-up = 16 years; maximum = 24 years). Compared with parous women without GDM, women with a history of GDM were not at increased risk of young-onset breast cancer overall (HR = 0.90; 95% CI: 0.78, 1.03) or by ER status (HR = 0.96; 95% CI: 0.79, 1.16 for ER-positive; HR = 1.07; 95% CI: 0.78, 1.47 for ER-negative). Compared with nulliparous women, parous women with a history of GDM had a lower risk of breast cancer overall (HR = 0.79; 95% CI: 0.68, 0.91) and of ER-positive (HR = 0.82; 95% CI: 0.66, 1.02) but not ER-negative (HR = 1.09; 95% CI: 0.76, 1.54) invasive breast cancer. These results were consistent with the HRs comparing parous women without GDM to nulliparous women.

CONCLUSIONS

Results of this analysis do not support the hypothesis that GDM is a risk factor for breast cancer in young women. Our findings suggest that the well-established protective effect of parity on risk of ER-positive breast cancer persists even for pregnancies complicated by GDM.

Gestational Diabetes Mellitus Among Asians - A Systematic Review From a Population Health Perspective

OBJECTIVE

Since Asians are particularly vulnerable to the risk of gestational diabetes mellitus (GDM), the lifecourse health implications of which are far beyond pregnancy, we aimed to summarize the literature to understand the research gaps on current GDM research among Asians.

METHODS

We systematically searched the articles in PubMed, Web of Science, Embase, and Scopus by 30 June 2021 with keywords applied on three topics, namely "GDM prevalence in Asians", "GDM and maternal health outcomes in Asians", and "GDM and offspring health outcomes in Asians".

RESULTS

We observed that Asian women (natives and immigrants) are at the highest risk of developing GDM and subsequent progression to type 2 diabetes among all populations. Children born to GDM-complicated pregnancies had a higher risk of macrosomia and congenital anomalies (i.e. heart, kidney and urinary tract) at birth and greater adiposity later in life.

CONCLUSION

This review summarized various determinants underlying the conversion between GDM and long-term health outcomes in Asian women, and it might shed light on efforts to prevent GDM and improve the lifecourse health in Asians from a public health perspective.

SYSTEMATIC REVIEW REGISTRATION

Prospero, CRD42021286075.

Is Gestational Diabetes Mellitus a Risk Factor of Maternal Breast Cancer? A Systematic Review of the Literature

The association between gestational diabetes mellitus (GDM) and breast cancer (BC) risk is complex. We aimed to examine this association in a systematic review of the literature. This review was done using the PubMed/Medline and Web of Science databases, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Newcastle-Ottawa Scale was used for the assessment of bias and quality of studies. Only English-language articles published before 1 June 2021, were included. Fourteen studies were included in this systematic review. Among them, eight did not find statistically significant results. Three studies showed a statistically significant increased risk of BC after GDM, and they explained this potential increased risk by hyperinsulinemia, hyperglycemia, and low-grade inflammation. However, three studies showed a statistically significant decreased risk of BC after GDM, suggesting a possible protective effect of hormonal changes induced by GDM during pregnancy. These controversial results should be interpreted with caution due to both quantitative and qualitative methodological shortcomings. Further investigations are thus needed in order to gain a better understanding of the associations between GDM and BC, and their underlying mechanisms.

Role of adipose tissue in regulating fetal growth in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a global health issue with significant short and long-term complications for both mother and baby. There is a strong need to identify an effective therapeutic that can prevent the development of GDM. A better understanding of the pathophysiology of GDM and the relationship between the adipose tissue, the placenta and fetal growth is required. The placenta regulates fetal growth by modulating nutrient transfer of glucose, amino acids and fatty acids. Various factors secreted by the adipose tissue, such as adipokines, adipocytokines and more recently identified extracellular vesicles, can influence inflammation and interact with placental nutrient transport. In this review, the role of the placental nutrient transporters and the adipose-derived factors that can influence their function will be discussed. A better understanding of these factors and their relationship may make a potential target for therapeutic interventions to prevent the development of GDM and its consequences.

The association between gestational diabetes mellitus and cancer in women: A systematic review and meta-analysis of observational studies

AIM

Both type 1 and type 2 diabetes are associated with greater risk of a variety of cancers. However, the association between gestational diabetes mellitus (GDM) and risk of cancer has so far not been well addressed. This study aimed to summarize the epidemiological evidence of the association between GDM and subsequent risk of cancer.

METHODS

PubMed and Embase databases were searched for relevant studies, and a random-effects model was used to calculate the summary relative risks (RRs) along with the corresponding 95% confidence intervals (CIs).

RESULTS

A total of 17 observational studies were selected, comprising 7 case-control and 10 cohort studies. Pooled effect estimates retrieved from these 17 studies showed that GDM was associated with an increased risk of breast cancer in Asia (pooled RR: 1.31, 95% CI: 1.01-1.70), but not in other regions, and also with thyroid cancer (RR: 1.28, 95% CI: 1.16-1.42), stomach cancer (RR: 1.43, 95% CI: 1.02-2.00) and liver cancer (RR: 1.27, 95% CI: 1.03-1.55). However, GDM was not associated with any increased risk of colon (RR: 1.41, 95% CI: 0.90-2.21), colorectal (RR: 1.16, 95% CI: 0.95-1.41), ovarian (RR: 1.14, 95% CI: 0.90-1.44), cervical (RR: 1.02, 95% CI: 0.81-1.29), pancreatic (RR: 3.49, 95% CI: 0.80-15.23), brain and nervous system (RR: 1.26, 95% CI: 0.80-1.97), blood (leukaemia, RR: 0.77, 95% CI: 0.45-1.30), endometrial (RR: 0.77, 95% CI: 0.20-2.98), skin (RR: 1.13, 95% CI: 0.81-1.59) or urological (RR: 0.98, 95% CI: 0.73-1.31) cancers.

CONCLUSION

GDM is associated with a greater risk of cancer in women, including breast, thyroid, stomach and liver cancers. However, further investigation is nonetheless warranted.

Incidence and relative risk for developing cancers in women with gestational diabetes mellitus: a nationwide cohort study in Taiwan

OBJECTIVES

To evaluate the risk of developing cancers, particularly site-specific cancers, in women with gestational diabetes mellitus (GDM) in Taiwan.

SETTING

The National Health Insurance Research Database (NHIRD) of Taiwan.

PARTICIPANTS

This study was conducted using the nationwide data from 2000 to 2013. In total, 1 466 596 pregnant women with admission for delivery were identified. Subjects with GDM consisted of 47 373 women, while the non-exposed group consisted of 943 199 women without GDM. The participants were followed from the delivery date to the diagnosis of cancer, death, the last medical claim or the end of follow-up (31 December 2013), whichever came first.

PRIMARY OUTCOME MEASURES

Patients with a new diagnosis of cancer (International Classification of Diseases, ninth edition, with clinical modification (ICD-9-CM codes 140-208)) recorded in NHIRD were identified. The risk of 11 major cancer types was assessed, including cancers of head and neck, digestive organs, lung and bronchus, bone and connective tissue, skin, breast, genital organs, urinary system, brain, thyroid gland and haematological system.

RESULTS

The rates of developing cancers were significantly higher in women with GDM compared with the non-GDM group (2.24% vs 1.96%; p<0.001). After adjusting for maternal age at delivery and comorbidities, women with GDM had increased risk of cancers, including cancers of nasopharynx (adjusted HR, 1.739; 95 % CI, 1.400 to 2.161; p<0.0001), kidney (AHR, 2.169; 95 % CI, 1.428 to 3.293; p=0.0003), lung and bronchus (AHR, 1.372; 95 % CI, 1.044 to 1.803; p=0.0231), breast (AHR, 1.234; 95% CI, 1.093 to 1.393; p=0.007) and thyroid gland (AHR, 1.389; 95 % CI, 1.121 to 1.721; p=0.0026).

CONCLUSION

Women with GDM have a higher risk of developing cancers. Cancer screening is warranted in women with GDM. Future research should be aimed at establishing whether this association is causal.

Gestational diabetes risk factors and long-term consequences for both mother and offspring: a literature review

INTRODUCTION

Established risk factors for gestational diabetes mellitus (GDM) include ethnicity, obesity, and family history of diabetes. Untreated GDM patients have higher rates of maternal and perinatal morbidity. GDM is an independent risk factor for future longer-term risk of type 2 diabetes mellitus (T2DM), metabolic syndrome, cardiovascular morbidity, malignancies, ophthalmic, psychiatric, and renal disease in the mother. Offspring risk long-term adverse health outcomes, including T2DM, subsequent obesity, impacted neurodevelopmental outcome, increased neuropsychiatric morbidity, and ophthalmic disease.

AREAS COVERED

We critically review data from retrospective, prospective, and meta-analysis studies pertaining to established GDM risk factors, complications during pregnancy and birth (both mother and offspring), and long-term consequences (both mother and offspring).

EXPERT COMMENTARY

Many of the adverse consequences of GDM might be avoided with proper management and treatment. Patients belonging to high-risk ethnic groups, and/or with body mass index ≥ 25 kg/m², and/or known history of diabetes in first-degree relatives may benefit from universal screening and diagnostic criteria proposed by the International Association of Diabetes and Pregnancy Study Group (IADPSG). The IADPSG one-step method has several advantages, including simplicity of execution, greater patient-friendliness, and higher diagnostic accuracy. Additionally, evidence suggests that the recent increased popularity of bariatric surgery will help to decrease GDM rates over next 5 years. Similarly, metformin may be useful for treating and preventing obstetrical complications in confirmed GDM patients.

Evaluation of the Association between Gestational Diabetes Mellitus at First Pregnancy and Cancer within 10 Years Postpartum Using National Health Insurance Data in South Korea

This study aims to evaluate the association between gestational diabetes mellitus (GDM) at first pregnancy and the incidence of cancer within 10 years postpartum. We used customized health information data from the National Health Insurance Corporation (NHIC). This retrospective cohort study included data from women who were not previously diagnosed with diabetes or any kind of malignancy in the National Health Screening Examination through the NHIC during 2002–2003, and only women who had their first delivery between 2004 and 2005 was included. Follow-up cancer diagnosis was carried out up until 2015. Among the 102,900 primiparous women, 4970 (4.83%) were diagnosed with GDM. During 10 year total follow-up period, 6569 (6.38%) cases of primary cancer were identified. The incidence of cancer was higher in women with GDM and the most common type of cancer was thyroid cancer, followed by breast cancer. On the basis of survival analysis, we adopted the Cox proportional hazards model and found that GDM was positively associated with cancer, particularly in thyroid cancer (HR: 1.27, 95% CI: 1.054–1.532, p = 0.012). However, the incidence of other malignancies (including ovarian and breast cancers) were not significantly associated with GDM, though they did show positive trends. Our findings suggest that GDM is associated with the incidence of cancer, particular thyroid cancer.

Potential Mechanisms underlying the Protective Effect of Pregnancy against Breast Cancer: A Focus on the IGF Pathway

A first full-term birth at an early age protects women against breast cancer by reducing lifetime risk by up to 50%. The underlying mechanism resulting in this protective effect remains unclear, but many avenues have been investigated, including lobular differentiation, cell fate, and stromal composition. A single pregnancy at an early age protects women for 30-40 years, and this long-term protection is likely regulated by a relatively stable yet still modifiable method, such as epigenetic reprograming. Long-lasting epigenetic modifications have been shown to be induced by pregnancy and to target the IGF pathway. Understanding how an early first full-term pregnancy protects against breast cancer and the role of epigenetic reprograming of the IGF system may aid in developing new preventative strategies for young healthy women in the future.

History of Gestational Diabetes Mellitus and Risk of Incident Invasive Breast Cancer among Parous Women in the Nurses' Health Study II Prospective Cohort

Background: Type II diabetes is associated with breast cancer in epidemiologic studies. Pregnancy also modifies breast cancer risk. We hypothesized that women with a history of gestational diabetes mellitus (GDM), which shares pathogenesis and risk factors with type II diabetes, would have greater invasive breast cancer risk than parous women without a history of GDM.Methods: We conducted a prospective analysis among parous women in the Nurses' Health Study II, with mean age 35 years in 1989. Multivariate Cox proportional hazards models were used to compare risks of incident invasive breast cancer in women with and without a history of GDM.Results: Among 86,972 women studied, 5,188 women reported a history of GDM and 2,377 developed invasive breast cancer (100 with history of GDM, 2,277 without GDM) over 22 years of prospective follow-up. History of GDM was inversely associated with incident invasive breast cancer [HR, 0.68; 95% confidence interval (CI), 0.55-0.84; P = 0.0004], compared with no history of GDM, after adjustment for body mass index, reproductive history, and other breast cancer risk factors. Findings were similar by menopausal status, although observed person-time was predominantly premenopausal (premenopausal: HR, 0.73; 95% CI, 0.56-0.96; P = 0.03; postmenopausal: HR, 0.63; 95% CI, 0.43-0.92; P = 0.02). Restricting to women undergoing mammography screening modestly attenuated the relationship (HR, 0.74; 95% CI, 0.57-0.96; P = 0.02).Conclusions: Among a large cohort of U.S. women, history of GDM was not associated with an elevated risk of subsequent invasive breast cancer.Impact: Our findings highlight the need to further investigate GDM's role in breast cancer development. Cancer Epidemiol Biomarkers Prev; 26(3); 321-7. ©2016 AACR.

Short-term risk of cancer among women with previous gestational diabetes: a population-based study

AIMS

To evaluate the relationship between gestational diabetes (GDM) and incidence of cancer in women within the first decade postpartum.

METHODS

This population-based retrospective cohort study compared the risk of cancer in women with GDM with that of a matched control group comprising pregnant women without diabetes. We included women from Ontario, Canada aged 20-50 years with no history of cancer who had given birth between 1995 and 2008 (N = 149 049). Women with GDM (N = 49 684) were matched on age and year of giving birth, in a ratio of 1:2, to pregnant women without diabetes (N = 99 365).

RESULTS

Over a median 8-year follow-up, there were a total of 2927 (1.5%) cancers. After adjustment for covariates, we found no significant difference in overall risk of cancer between women with GDM and matched control subjects; however, GDM was associated with a significantly greater risk of thyroid cancer (adjusted hazard ratio 1.24, 95% CI 1.05, 1.46) and a significantly lower risk of premenopausal breast cancer (hazard ratio 0.86, 95% CI 0.75, 0.98) compared with matched control subjects.

CONCLUSIONS

This large population-based study did not find a greater risk of cancers among women with GDM during the first decade postpartum; however, GDM was associated with a higher risk of thyroid cancer and a lower risk of premenopausal breast cancer. Further studies are needed to confirm these findings.

Socioeconomic disparities in breast cancer incidence and survival among parous women: findings from a population-based cohort, 1964-2008

Background

Socioeconomic position (SEP) has been associated with breast cancer incidence and survival. We examined the associations between two socioeconomic indicators and long-term breast cancer incidence and survival in a population-based cohort of parous women.

Methods

Residents of Jerusalem who gave birth between 1964–1976 (n = 40,586) were linked to the Israel Cancer Registry and Israel Population Registry to determine breast cancer incidence and vital status through mid-2008. SEP was assessed by husband’s occupation and the woman’s education. We used log ranks tests to compare incidence and survival curves by SEP, and Cox proportional hazard models to adjust for demographic, reproductive and diagnostic factors and assess effect modification by ethnic origin.

Results

In multivariable models, women of high SEP had a greater risk of breast cancer compared to women of low SEP (Occupation: HR 1.18, 95 % CI 1.03-1.35; Education: HR 1.39, 95 % CI 1.21-1.60) and women of low SEP had a greater risk of mortality after a breast cancer diagnosis (Occupation: HR 1.33, 95 % CI 1.04-1.70; Education: HR 1.37, 95 % CI 1.06-1.76). The association between education and survival was modified by ethnic origin, with a gradient effect observed only among women of European origin. Women of Asian, North African and Israeli origin showed no such trend.

Conclusions

SEP was associated with long-term breast cancer incidence and survival among Israeli Jews. Education had a stronger effect on breast cancer outcomes than occupation, suggesting that a behavioral mechanism may underlie disparities. More research is needed to explain the difference in the effect of education on survival among European women compared to women of other ethnicities.

Association between gestational diabetes mellitus and subsequent risk of cancer: a systematic review of epidemiological studies

PURPOSE

This study aimed at summarizing epidemiological evidence of the association between gestational diabetes mellitus (GDM) and subsequent risk of cancer.

MATERIALS AND METHODS

We searched Medline, Embase, Cancer Lit and CINAHL for epidemiological studies published by February 1, 2014 examining the risk of cancer in patients with history of GDM using highly inclusive algorithms. Information about first author, year of publication, country of study, study design, cancer sites, sample sizes, attained age of subjects and methods used for determining GDM status were extracted by two researchers and Stata version 11.0 was used to perform the meta-analysis and estimate the pooled effects.

RESULTS

A total of 9 articles documented 5 cohort and 4 case- control studies containing 10,630 cancer cases and 14,608 women with a history of GDM were included in this review. Taken together, the pooled odds ratio (OR) between GDM and breast cancer risk was 1.01 (0.87-1.17); yet the same pooled ORs of case-control and cohort studies were 0.87 (0.71-1.06) and 1.25 (1.00-1.56) respectively. There are indications that GDM is strongly associated with higher risk of pancreatic cancer (HR=8.68) and hematologic malignancies (HR=4.53), but no relationships were detected between GDM and other types of cancer.

CONCLUSIONS

Although GDM increases the risk of certain types of cancer, these results should be interpreted with caution becuase of some methodological flaws. The issue merits added investigation and coordinated efforts between researchers, antenatal clinics and cancer treatment and registration agencies to help attain better understanding.

Pregnancy-related characteristics and breast cancer risk

Breast tissues undergo extensive physiologic changes during pregnancy, which may affect breast carcinogenesis. Gestational hypertension, preeclampsia/eclampsia, gestational diabetes, pregnancy weight gain, and nausea and vomiting (N&V) during pregnancy may be indicative of altered hormonal and metabolic profiles and could impact breast cancer risk. Here, we examined associations between these characteristics of a woman's pregnancy and her subsequent breast cancer risk. Participants were parous women that were recruited to a population-based case-control study (Western New York Exposures and Breast Cancer Study). Cases (n = 960), aged 35-79 years, had incident, primary, histologically confirmed breast cancer. Controls (n = 1,852) were randomly selected from motor vehicle records (< 65 years) or Medicare rolls (≥ 65 years). Women were queried on their lifetime pregnancy experiences. Multivariable-adjusted logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). N&V during pregnancy was inversely associated with breast cancer risk. Relative to those who never experienced N&V, ever experiencing N&V was associated with decreased risk (OR 0.69, 95% CI 0.56-0.84) as were increased N&V severity (p trend < 0.001), longer duration (p trend < 0.01), and larger proportion of affected pregnancies (p trend < 0.0001) among women with ≥ 3 pregnancies. Associations were stronger for more recent pregnancies (< 5 years). Findings did not differ by menopausal status or breast cancer subtype including estrogen receptor and HER2 expression status. Other pregnancy characteristics examined were not associated with risk. We observed strong inverse associations between pregnancy N&V and breast cancer risk. Replication of these findings and exploration of underlying mechanisms could provide important insight into breast cancer etiology and prevention.

A linked-registry study of gestational factors and subsequent breast cancer risk in the mother

BACKGROUND

Women who were younger at their first live birth have a reduced breast cancer risk. Other pregnancy characteristics, including complications, also may affect risk but because they are rare, require large datasets to study.

METHODS

The association of pregnancy history and breast cancer risk was assessed in a population-based study including 22,646 cases diagnosed in Washington State 1974 to 2009, and 224,721 controls, frequency matched on parity, age, calendar year of delivery, and race/ethnicity. Information on prediagnosis pregnancies derived from linked birth certificate and hospital discharge databases. Adjusted odd ratios (ORs) and 95% confidence intervals (CI) were calculated.

RESULTS

Multiple gestation pregnancies were associated with decreased breast cancer risk (OR, 0.65; 95% CI, 0.57-0.74) as was prepregnancy obesity (OR, 0.76; 95% CI, 0.65-0.90). Infant birth weight was positively associated (6% per 1,000 g; 95% CI, 3%-9%). The ORs for first trimester bleeding (OR, 3.35; 95% CI, 1.48-7.55) and placental abnormality/insufficiency (OR, 2.24; 95% CI, 1.08-4.67) were increased in women diagnosed at age 50+ years and 15+ years after the index pregnancy. Results were similar in analyses restricted to first pregnancies, those closest to diagnosis, and when excluding in situ disease.

CONCLUSION

These data suggest that multiple gestation pregnancies are protective, whereas delivering larger infants increases risk for later development of maternal breast cancer. Placental abnormalities that result in bleeding in pregnancy also may reverse the long-term protection in postmenopausal women associated with parity.

IMPACT

Certain pregnancy characteristics seem to be associated with later maternal breast cancer risk.

Risk of esophagus cancer in diabetes mellitus: a population-based case-control study in Taiwan

Background

Diabetes mellitus (DM) has been associated with the cancer risk. This study investigated relationship between DM and esophageal cancer using Taiwan’s insurance data.

Methods

We identified 549 patients with esophageal cancer newly diagnosed in 2000-2009 and randomly selected 2196 controls without any cancer, frequency matched by sex, age and diagnosis year of cases. Logistic regression model estimated odds ratios (ORs) and 95% confidence intervals (CI) of esophageal cancer associated with DM, sex, age. co-morbidities and medications.

Results

Cases were more prevalent than controls for alcoholism and esophageal disorders and using nonsteroidal anti-inflammatory drugs (NSAIDs) and cyclooxygenase-2 inhibitors but not DM. Esophageal cancer had no association with DM (OR 0.99, 95% CI 0.71-1.37), but significantly associated with alcoholism (OR 14.1, 95% CI 7.87-25.4), esophageal ulcer (OR 10.1, 95% CI 5.70-17.9), esophageal reflux (OR 3.47, 95% CI 2.14-5.26) and uses of NSAIDs (OR 2.73, 95% CI 1.80-4.13). An elevated risk of esophageal cancer appeared in DM patients taking insulin (OR 2.57, 95% CI 1.08-6.15) or sulfonyurea (OR 3.80, 95% CI 1.16-12.5).

Conclusions

Patients with DM are not at higher risk for esophagus cancer. However, esophageal disorders and anti-diabetic drugs are associated with the risk of the disease.

Diabetes increases the risk of breast cancer: a meta-analysis

The aim of this meta-analysis was to collate and analyse all primary observational studies investigating the risk of breast cancer (BC) associated with diabetes. In addition, we aimed to complete subgroup analyses by both type of diabetes and gender of study participants to further clarify the origin of any such association between the two. Studies were obtained from a database search of MEDLINE, EMBASE, PubMed, Current Contents Connect and Google Scholar with additional cross-checking of reference lists. Collated data were assessed for heterogeneity and a pooled odds ratio (OR) calculated. Forty-three studies were included in the meta-analysis with 40 studies investigating BC in women and six studies investigating BC in men. Overall, we found a significantly increased risk of BC associated with diabetes in women (OR 1.20, 95% confidence interval (CI) 1.13-1.29). After subgroup analysis by type of diabetes, the association was unchanged with type 2 diabetes (OR 1.22, 95% CI 1.07-1.40) and nullified with gestational diabetes (OR 1.06, 95% CI 0.79-1.40). There were insufficient studies to calculate a pooled OR of the risk of BC associated with type 1 diabetes. There was an increased risk of BC in males with diabetes mellitus; however, the results did not reach statistical significance (OR 1.29, 95% CI 0.99-1.67). In conclusion, diabetes increases the risk of BC in women. This association is confirmed in women with type 2 diabetes and supports the hypothesis that diabetes is an independent risk factor for BC.

Gestational diabetes and risk of incident primary cancer: a large historical cohort study in Israel

PURPOSE

Gestational diabetes mellitus (GDM), a state of glucose intolerance associated with pregnancy, is increasing in prevalence. Data regarding the cancer risk associated with GDM are sparse and limited to cancers of the breast and pancreas. This study was conducted to examine the risk of incident overall and site-specific malignancies associated with prior GDM in a historical cohort of women in a large health maintenance organization in Israel.

METHODS

All pregnant women aged 15-50 years who underwent 50-g glucose challenge tests between 13 March 1995 and 27 May 2009, without history of malignancy, diabetes, and infertility, were included. Clinical and demographic parameters at index date including age, socioeconomic level, BMI, and parity were collected. Diagnosis of gestational diabetes was based on the 100-g oral glucose tolerance test using Carpenter and Coustan criteria. Cancer diagnoses were obtained from the Israel Cancer Register through linkage data.

RESULTS

Among the 185,315 women who had undergone glucose challenge during the study period, 11,264 (6.1%) were diagnosed with GDM. During a total follow-up period of 1.05 million person-years (mean = 5.19 ± 3.9, median = 4.3), 2,034 incident cases of cancer were identified. GDM was associated with a hazard ratio (HR) of 7.06 (95% CI: 1.69-29.45) for pancreatic cancer (nine cases) and a HR of 1.70 (95% CI: 0.97-2.99) for hematological malignancies (177 cases). The association between GDM and hematological malignancies was limited to women with 5 or more years of follow-up (HR = 4.53; 95% CI: 1.81-11.31).

CONCLUSION

GDM is associated with an increased risk of pancreatic cancer and hematologic malignancies.

Pregnancy characteristics and maternal breast cancer risk: a review of the epidemiologic literature

The short- and long-term effects of pregnancy on breast cancer risk are well documented. Insight into potential biological mechanisms for these associations may be gained by studying breast cancer risk and pregnancy characteristics (e.g., preeclampsia, twining), which may reflect hormone levels during pregnancy. To date, no review has synthesized the published literature for pregnancy characteristics and maternal breast cancer using systematic search methods. We conducted a systematic search to identify all published studies. Using PUBMED (to 31 July 2009), 42 relevant articles were identified. Several studies suggest that multiple births may be associated with a lowered breast cancer risk of about 10-30%, but results were inconsistent across 18 studies. The majority of 13 studies suggest about a 20-30% reduction in risk with preeclampsia and/or gestational hypertension. Six of seven studies reported no association for infant sex and breast cancer risk. Data are sparse and conflicting for other pregnancy characteristics such as gestational age, fetal growth, pregnancy weight gain, gestational diabetes, and placental abnormalities. The most consistent findings in a generally sparse literature are that multiple births and preeclampsia may modestly reduce breast cancer risk. Additional research is needed to elucidate associations between pregnancy characteristics, related hormonal profiles, and breast cancer risk.

Glucose metabolism disorders in cancer patients in a Chinese population

BACKGROUND

Characteristics of glucose metabolism disorders (GMDs) in different cancers and the contributory role of GMDs in developing cancers are still not so clear.

METHODS

Two thousand four hundred and five patients with malignancy who had been hospitalized in the First Affiliated Hospital of Jinan University were pooled as case group. Two thousand and sixteen non-cancer people who finished health examinations in the Affiliated Yangcheng Hospital of Guangzhou Medical College were enrolled as control group. We compared glucose metabolism among patients with different kinds of malignancy. Based on logistic regression models, we analyzed factors that affect the development of carcinoma.

RESULTS

(1) Among 2,408 malignancy patients, the total prevalence of diabetes mellitus (DM) and impaired fasting glucose (IFG) reached 28.0%. Pancreatic cancer, lymphoma, liver cancer, leukemia, and colorectal cancer showed most striking hyperglycemia. (2) Leukemia and esophageal cancer accounting for 12.5% and 12.1%, respectively, were the most likely to suffer from hypoglycemia. (3) Older cancer patients seem to be more vulnerable to hyperglycemia, while the younger tend to be more likely to develop hypoglycemia. (4) High level of fasting plasma glucose (FPG) was associated with lung cancer, breast cancer, leukemia, lymphoma, thyroid cancer, bladder cancer, and pancreatic cancer. Patients with DM increased risks for developing colorectal cancer, liver cancer, esophageal cancer, thyroid cancer, cervical cancer, and pancreatic cancer.

CONCLUSIONS

GMDs are frequent events in malignancy patients. Hyperglycemia and hypoglycemia are found in the same kinds or different kinds of cancers, and the incidence of hyperglycemia is higher than that of hypoglycemia. Characteristics of GMDs were dissimilar in different cancers and different ages. Hyperglycemia was a risk factor for many cancers.

Acute maternal stress in pregnancy and schizophrenia in offspring: a cohort prospective study

Schizophrenia has been linked with intrauterine exposure to maternal stress due to bereavement, famine and major disasters. Recent evidence suggests that human vulnerability may be greatest in the first trimester of gestation and rodent experiments suggest sex specificity. We aimed to describe the consequence of an acute maternal stress, through a follow-up of offspring whose mothers were pregnant during the Arab-Israeli war of 1967. A priori, we focused on gestational month and offspring's sex.

METHOD

In a pilot study linking birth records to Israel's Psychiatric Registry, we analyzed data from a cohort of 88,829 born in Jerusalem in 1964-76. Proportional hazards models were used to estimate the relative risk (RR) of schizophrenia, according to month of birth, gender and other variables, while controlling for father's age and other potential confounders. Other causes of hospitalized psychiatric morbidity (grouped together) were analyzed for comparison.

RESULTS

There was a raised incidence of schizophrenia for those who were in the second month of fetal life in June 1967 (RR = 2.3, 1.1-4.7), seen more in females (4.3, 1.7-10.7) than in males (1.2, 0.4-3.8). Results were not explained by secular or seasonal variations, altered birth weight or gestational age. For other conditions, RRs were increased in offspring who had been in the third month of fetal life in June 1967 (2.5, 1.2-5.2), also seen more in females (3.6, 1.3-9.7) than males (1.8, 0.6-5.2).

CONCLUSION

These findings add to a growing literature, in experimental animals and humans, attributing long term consequences for offspring of maternal gestational stress. They suggest both a sex-specificity and a relatively short gestational time-window for gestational effects on vulnerability to schizophrenia.

Population-based case-control study of diabetes and breast cancer risk in Hispanic and non-Hispanic White women living in US southwestern states

Diabetes mellitus has been associated with breast cancer, although no studies appear to have adequately assessed the association in Hispanic women, a population with a high prevalence of diabetes. The authors investigated this association in a population-based case-control study of Hispanic and non-Hispanic White women living in the southwestern United States. Breast cancer cases diagnosed in 1999-2004 were identified through state cancer registries (1,526 non-Hispanic Whites, 798 Hispanics). Age- and ethnicity-matched controls (1,599 non-Hispanic Whites, 924 Hispanics) were selected from commercial mailing lists and driver's license and Social Security records. Diabetes history was assessed through interviewer-administered questionnaires. Odds ratios and 95% confidence intervals were calculated using logistic regression, adjusting for age, body mass index at age 15 years, and parity. Having any type of diabetes was not associated with breast cancer overall (odds ratio = 0.94, 95% confidence interval: 0.78, 1.12). Type 2 diabetes was observed among 19% of Hispanics and 9% of non-Hispanic Whites but was not associated with breast cancer in either group. Gestational diabetes was inversely associated with breast cancer in both ethnic groups, especially when first diagnosed at age < or =35 years (odds ratio = 0.54, 95% confidence interval: 0.37, 0.79). In this study, diabetes was not associated with breast cancer overall, although the inverse association with gestational diabetes warrants further investigation.