Parity and risk of diabetes in a Danish nationwide birth cohort

Are pregnancy and parity associated with telomere length? A systematic review

BACKGROUND

Women's reproduction requires increased energy demands, which consequently may lead to cellular damage and aging. Hence, Telomere Length (TL), a biomarker of biological aging and health status may possibly serve as a biomarker of reproductive effort. The aim of this systematic review is to evaluate telomere dynamics throughout pregnancy and the association between parity and TL.

METHODS

A systematic search was conducted across seven databases including CINAHL, Cochrane, PsycINFO, Proquest, PubMed; Scopus; and Web of Science, using keywords and MeSH descriptors of parity and TL. Predefined inclusion and exclusion criteria were used to screen abstracts and titles. After the removal of duplicates, 3431 articles were included in the primary screening, narrowed to 194 articles included in the full-text screening. Consensus was reached for the 14 studies that were included in the final review, and the Newcastle-Ottawa scale (NOS) was utilized to assess the quality of the selected studies. A mini meta-analysis utilized JASP 0.17.3 software and included 4 applicable studies, comprising a total of 2564 participants to quantitatively assess the estimated effect size of parity on TL.

RESULTS

Of the 11 studies reviewed on parity and TL, four demonstrated a negative correlation; one - a positive correlation and six -found no correlation. Studies demonstrating a negative correlation encompassed rigorous methodological practices possibly suggesting having more children is associated with enhanced telomere attrition. Of the four longitudinal studies assessing telomere dynamics throughout pregnancy, most found no change in TL from early pregnancy to postpartum suggesting pregnancy does not affect TL from early pregnancy to early postpartum. The meta-analysis revealed a negative, yet, non-significant effect, of the estimated effect size of parity on TL(ES = -0.009, p = 0.126, CI -0.021, 0.03).

CONCLUSIONS

Studies assessing pregnancy, parity and TL yielded mixed results, most likely due to the different research methods utilized in each study. Improvements in study design to better understand the short-term effects of pregnancy on TL and the effect of parity on TL over time, include precise definitions of parity, comparisons of different age groups, inclusion of reproductive lifespan and statistically adjusting for potential confounders in the parity and TL relationship.

The relationship between pregnancy count and duration of breast-feeding with metabolic syndrome (Fasa Persian cohort study)

BACKGROUND

Changes that occur during pregnancy and after that during breastfeeding induce some symptoms similar to metabolic syndrome (MetS) risk factors. This study aims to determine the relationship between pregnancy, as well as the duration of breastfeeding and MetS controlling the effect of other risk factors like hypertension, glucose intolerance, triglyceride, central obesity, and reduction of high-density lipoprotein in women of Fasa Persian Cohort Study.

MATERIALS AND METHODS

In this cross-sectional study, 5015 women aged 35-70 years were investigated in the Sheshdeh region from 2016 to 2021, and the information related to the disease symptoms was collected through questionnaires, examinations, and laboratory tests. MetS was calculated based on two guidelines according to adult treatment panel III (ATP III) and international diabetes federation (IDF) methods. For reporting the data, the odds ratio with its 95% confidence interval was used. In order to eliminate the effect of confounders, logistic regression was used.

RESULTS

Prevalence of MetS showed a descending trend in women with up to two pregnancies and it reached 22.6% and 22.4% using ATPIII and IDF methods respectively, while with an increase in the number of pregnancies of more than two, MetS prevalence was ascending. The prevalence of MetS did not have any specific trend across various breastfeeding duration groups. Multivariate analysis approved that the odds ratio of developing MetS in comparison with women who had two pregnancies was significantly increasing trend when the pregnancy counts increased.

CONCLUSION

The chance of developing MetS based on both IDF and ATP III methods after adjustment for confounding effects would grow with an increase in the number of pregnancies to more than two and breast-feeding of more than seven years. It is recommended that women with more than two pregnancies or the long duration of breast-feeding women undergo a specialized examination to investigate and control MetS problems so that future diseases could be prevented.

Parity and incident type 2 diabetes in older Chinese women: Guangzhou Biobank Cohort Study

This study examined the association between parity and incident type 2 diabetes in older Chinese women and estimated the mediation effect of adiposity indicators. A total of 11,473 women without diabetes at baseline from 2003 to 2008 were followed up until 2012. We used Cox proportional hazards regression to assess the association between parity and incident type 2 diabetes, and mediation analysis to estimate the mediation effect of adiposity indicators. Compared to women with one parity, the hazard ratio (HR) (95% confidence interval (CI)) for incident type 2 diabetes was 0.85 (0.44-1.63), 1.20 (1.11-1.30), 1.28 (1.16-1.41) and 1.27 (1.14-1.42) for women with parity of 0, 2, 3, and ≥ 4, respectively. The proportion of indirect effect (95% CI) mediated by body mass index, waist circumference, hip circumference, waist-to-hip ratio, waist-to-height ratio and body fat percentage was 26.5% (19.2-52.2%), 54.5% (39.4-108.7%), 25.1% (18.2-49.1%), 35.9% (25.6-74.1%), 50.3% (36.5-98.6%) and 15.1% (- 66.4 to 112.3%), respectively. Compared to women with one parity, women with multiparity (≥ 2) had a higher risk of incident type 2 diabetes and up to half of the association was mediated by abdominal obesity.

Number of children and disability pension due to mental and musculoskeletal disorders: A longitudinal register-based study in Norway

Earlier research has documented a relationship between parity and all-cause mortality, as well as parity and cause-specific mortality (e.g. cancer and cardiovascular disease mortality). Less is known about the relationship between parity and two very common (but less deadly) types of disorder: mental and musculoskeletal. We examine the association between parity and risk of disability pensioning from all causes and due to mental or musculoskeletal disorders, using Norwegian register data. In addition to controlling for adult socio-demographic characteristics, we control for unobserved confounding from family background by estimating sibling fixed-effects models. We find a higher risk of disability pensioning among the childless and those with one child than for parents with two children, both for all causes combined and for mental disorders. Childless men and fathers with one child also experience excess risk of being pensioned due to musculoskeletal disorders. For mental disorders, we find a positive association with high parity, particularly for men.

Associations of reproductive factors with postmenopausal follicle stimulating hormone

Purpose

Recent studies have suggested that higher postmenopausal follicle stimulating hormone (FSH) may be associated with lower risk of diabetes. However, relatively little is known about postmenopausal FSH levels, including the level of variation between women and whether reproductive factors are associated with this variation.

Methods

We assessed the relationship of multiple reproductive factors with FSH levels among 588 postmenopausal women in the Kuopio Ischaemic Heart Disease Risk Factor Study. Participants were aged 53 to 73 years and not using hormone therapy at study enrollment (1998–2001) when reproductive factors were assessed and FSH was measured.

Results

After adjustment for age, menopause timing, sex steroid levels, adiposity and behavioral factors, we observed numbers of pregnancies and age at first birth were each inversely associated with FSH levels. For example, women with ≥ 3 births and an age at first birth ≥ 25 years had mean FSH levels that were 7.8 IU/L lower than those of women with 1–2 births and an age at first birth ≤ 24 years (P = 0.003). Number of miscarriages was inversely associated with FSH levels (-2.7 IU/L per miscarriage; P = 0.02). Women reporting 4 or more years of past hormone therapy use had significantly higher mean FSH levels than women who had never used hormone therapy (P for trend = 0.006).

Conclusion

Multiple reproductive factors were associated with postmenopausal FSH, independent of estradiol, adiposity and other confounders. These findings warrant replication and further exploration of potential underlying mechanism.

Number of Births and Risk of Diabetes in China's Older Women

As an important life event in individuals' life, childbirth will affect the health of women to different degrees. More and more attention has been paid to whether the number of births will affect the incident diabetes in elderly women, but there are few related studies. Based on the data of the Chinese Longitudinal Healthy Longevity Survey in 2018, 6,159 older women are selected as the study population. Logistic regression analyses are used to estimate the relationship between the number of births and diabetes risk. For each additional birth, the odds ratio of maternal diabetes will decrease by 6.9% and the result is significant at the 1% level, especially among mothers having four children or less. The conclusion is equally applicable in the sample of fathers and urban mothers, but the increase in the number of births will increase the risk of diabetes in rural mothers, although this result is not statistically significant. Later age at first birth, later age at last birth, the longer childbearing period, and birth interval will significantly reduce the risk of diabetes.

The association of parity/live birth number with incident type 2 diabetes among women: over 15 years of follow-up in The Tehran Lipid and Glucose Study

Background

Childbearing may increase the future risk of developing type 2 diabetes mellitus (T2DM) in mothers. However, the issue is not clear completely and not investigated in the Middle East, a region with a high burden of T2DM. In the current study, we examined the association of parity/live birth number with incident T2DM among Iranian women.

Methods

The study population included 2552 women aged 30–65 years recruited in 1999–2001 and were followed for incident T2DM by 3-year intervals. Multivariable Cox proportional hazard models were applied to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the parity/live birth number for incident T2DM. Parity number was defined as the number of live childbirth (number of live birth) plus the number of stillbirth (defined as birth of an infant that died after the 20th week of pregnancy in the uterus).

Results

During a median follow-up of 15.4 years, 557 incident T2DM cases have occurred. After adjustment for potential T2DM risk factors and reproductive factors, each additional parity caused a 9% higher risk for incident T2DM. Moreover, compared to women with one parity, those with 3 and ≥ 4 parity had HRs of 1.73 [95% CI: 1.06–2.83] and 2.23 [1.36–3.65], respectively. After further adjustment for body mass index (BMI) and waist circumference, although the HRs were attenuated prominently, parity ≥ 4 was associated with significantly higher risk (HR: 1.72 [1.05–2.83]); even after further adjustment for triglycerides (TG)/ high-density lipoprotein cholesterol (HDL-C), the risk remained marginally significant (HR: 1.64 [1.00–2.70; P value: 0.051]). For the number of live birth, the results were also similar. Moreover, in a sensitivity analysis, when we considered BMI change during follow-up as another covariate, generally, the effect sizes did not change; the trend of HRs across categories of parity number remained marginally significant (P value: 0.064).

Conclusions

During a long-term follow-up, after adjustment for potential T2DM risk factors, reproductive factors, obesity indices, and TG/HDL-C (insulin resistance surrogate), we demonstrated that higher parity/live birth numbers could be associated with increased risk of T2DM development among Iranian women. Moreover, even after further adjustment for BMI change, the suggestive higher risk was still found.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-021-01519-7.

The association between parity, CVD mortality and CVD risk factors among Norwegian women and men

BACKGROUND

Several studies have shown that women and men with two children have lower mortality than the childless, but there is less certainty about mortality, including CVD mortality, at higher parities and meagre knowledge about factors underlying the parity-mortality relationship.

METHODS

The association between parity and CVD mortality was analyzed by estimating discrete-time hazard models for women and men aged 40-80 in 1975-2015. Register data covering the entire Norwegian population were used, and the models included a larger number of relevant sociodemographic control variables than in many previous studies. To analyze the relationship between parity and seven CVD risk factors, logistic models including the same variables as the mortality models were estimated from the CONOR collection of health surveys, linked to the register data.

RESULTS

Men (but not women) who had four or more children had higher mortality from CVD than those with two, although this excess mortality was not observed for the heart disease sub-group. Overweight, possibly in part a result of less physical activity, seems to play a role in this. All CVD risk factors except smoking and alcohol may contribute to the relatively high CVD mortality among childless.

CONCLUSIONS

Childbearing is related to a number of well-known CVD risk factors, and becoming a parent or having an additional child is, on the whole, associated with lower-or at least not higher-CVD mortality in Norway. However, for men family sizes beyond three children are associated with increased CVD mortality, with risks of overweight one possible pathway.

Number of children and the prevalence of later-life major depression and insomnia in women and men: findings from a cross-sectional study of 0.5 million Chinese adults

BACKGROUND

Pregnancy and parenthood have been associated with physical and mental health. Previous literature concerning the impacts of parity on mental health was inconsistent and lack epidemiolocal evidence. China, with growing mental health problems and changing fertility patterns, faces unique challenges. This study aims to examine the relationship between parity and the prevalence of major depression and insomnia among men and women in the Chinese population.

METHODS

Baseline data from a Chinese population-based study of 512,891 adults (59.01% women) from 10 areas, aged 30-79 were analyzed. Number of children was based on self-report by the participants. Major depression (MD) was assessed using the Composite International Diagnostic Inventory. Insomnia symptoms were accessed by a questionnaire comparable to that used in the Diagnostic and Statistical Manual of Mental Disorders. Logistic regression was used to assess the relationship between MD/Insomnia and number of children, after stratifications and adjustments.

RESULTS

For women, each additional child was associated with a 9% decreased odds of MD (OR: 0.91, 95%CI: 0.88-0.96), with the associations significant for those who lived in urban areas (OR: 0.76, 95%CI: 0.70-0.83), or had a lower education (OR: 0.90, 95%CI: 0.85-0.94), or had lower household income (OR: 0.89, 95%CI: 0.85-0.94), or had ever used alcohol (OR: 0.89, 95%CI: 0.84-0.93). The association between per additional children and MD was not significant in men (OR: 1.02, 95%CI: 0.97-1.07), but a decreased odd of MD with per additional child was found in men who lived in urban areas (OR: 0.81, 95%CI: 0.71-0.96). For women, each additional child was associated with a 4% decreased odds of insomnia (OR: 0.96, 95%CI: 0.95-0.96). Each additional child was also associated with a 2% decreased odds of insomnia in men (OR: 0.98, 95%CI: 0.97-1.00).

CONCLUSIONS

MD and insomnia were inversely associated with number of children in women while the association was not overall significant in men. The association was mediated by socioeconomic and lifestyle factors. Future mental health public health programs should address parity and sex differences when designing interventions.

Pregnancy, pregnancy loss and the risk of diabetes in Chinese women: findings from the China Kadoorie Biobank

Pregnancy and pregnancy loss may be associated with increased risk of diabetes in later life. However, the evidence is inconsistent and sparse, especially among East Asians where reproductive patterns differ importantly from those in the West. We examined the associations of pregnancy and pregnancy loss (miscarriage, induced abortion, and still birth) with the risk of incident diabetes in later life among Chinese women. In 2004-2008, the nationwide China Kadoorie Biobank recruited 302 669 women aged 30-79 years from 10 (5 urban, 5 rural) diverse localities. During 9.2 years of follow-up, 7780 incident cases of diabetes were recorded among 273,383 women without prior diabetes and cardiovascular disease at baseline. Cox regression yielded multiple-adjusted hazard ratios (HRs) for the risk of diabetes associated with pregnancy and pregnancy loss. Overall, 99% of women had been pregnant, of whom 10%, 53%, and 6% reported having a history of miscarriage, induced abortion, and stillbirth, respectively. Among ever pregnant women, each additional pregnancy was associated with an adjusted HR of 1.04 (95% CI 1.03; 1.06) for diabetes. Compared with those without pregnancy loss, women with a history of pregnancy loss had an adjusted HR of 1.07 (1.02; 1.13) and the HRs increased with increasing number of pregnancy losses, irrespective of the number of livebirths; the adjusted HR was 1.03 (1.00; 1.05) for each additional pregnancy loss. The strength of the relationships differed marginally by type of pregnancy loss. Among Chinese women, a higher number of pregnancies and pregnancy losses were associated with a greater risk of diabetes.

Multiple pregnancies and the risk of diabetes mellitus in postmenopausal women

OBJECTIVE

We aimed to investigate whether the number of pregnancies during childbearing age was associated with diabetes in postmenopausal women with no history of gestational diabetes.

METHODS

Our data source was the continuous National Health and Nutrition Examination Survey 1999 to 2014. We selected 9,138 postmenopausal women over 40 years old who did not have a history of gestational diabetes during pregnancy. Logistic regression analyses were applied for the association of the number of pregnancies with diabetes.

RESULTS

We found women with ≥4 pregnancies had significantly greater fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), 2-hour plasma glucose, and the Homeostatic Model Assessment of Insulin Resistance than those with two to three pregnancies (all P < 0.01). These women also had a significantly higher prevalence of diabetes (28.4% vs 20.7%; P < 0.001). Using the two to three pregnancies group as the reference, we observed a positive association of log-FPG and log-HbA1c with 4 or more pregnancies after adjustment for sociodemographic, lifestyle, and reproductive factors, and body mass index (both P < 0.05). Compared to women with two to three pregnancies, the odds ratios for diabetes were 1.31 (95% confidence interval [CI] 1.01-1.71) for women who never got pregnant and 1.28 (95% CI 1.10-1.48) for those with at least 4 pregnancies after multivariate adjustment.

CONCLUSIONS

At least 4 pregnancies through childbearing age may be a potential risk factor for diabetes in postmenopausal women without a history of gestational diabetes.

Pregnancy in human IAPP transgenic mice recapitulates beta cell stress in type 2 diabetes

AIMS/HYPOTHESIS

Islet amyloid polypeptide (IAPP) misfolding and toxic oligomers contribute to beta cell loss and stress in type 2 diabetes. Pregnancy-related diabetes predicts subsequent risk for type 2 diabetes but little is known about the impact of pregnancy on beta cell mass, turnover and stress. Availability of human pancreas tissue in pregnancy is limited and most widely used mouse models of type 2 diabetes do not develop pregnancy-related diabetes, possibly because rodent IAPP is not prone to form toxic oligomers. We hypothesised that mice transgenic for human IAPP (hIAPP) are prone to pregnancy-related diabetes with beta cell responses reflective of those in type 2 diabetes.

METHODS

We evaluated the impact of a first and second pregnancy on glucose homeostasis, beta cell mass and turnover and markers of beta cell stress in hIAPP transgenic (hTG) mice.

RESULTS

Pregnancy induced both endoplasmic reticulum stress and oxidative stress and compromised autophagy in beta cells in hTG mice, which are characteristic of beta cells in type 2 diabetes. Beta cell stress persisted after pregnancy, resulting in subsequent diabetes before or during a second pregnancy.

CONCLUSIONS/INTERPRETATION

High expression of hIAPP in response to pregnancy recapitulates mechanisms contributing to beta cell stress in type 2 diabetes. We hypothesise that, in individuals prone to type 2 diabetes, pregnancy-induced increased expression of IAPP inflicts beta cell damage that persists and is compounded by subsequent additive stress such as further pregnancy. The hTG mouse model is a novel model for pregnancy-related diabetes.

Pregnancy history and cognitive aging among older women: the Rancho Bernardo Study

OBJECTIVE

The aim of the study was to examine the association of pregnancy history with trajectories of cognitive function in older women.

METHODS

Participants were 1,025 women (mean age = 73.1 ± 9.6 y) enrolled in the Rancho Bernardo Study who attended a clinic visit between 1988 and 1992, when pregnancy history (ever pregnant, number of pregnancies, ages at first and last pregnancy) was recorded and cognitive function was assessed with a battery of four tests repeated up to 7 times through 2016. Linear mixed-effects regression models were used to examine the association between pregnancy history and longitudinal change in cognitive function.

RESULTS

Overall, 77% of women had at least one pregnancy; number of pregnancies ranged from 1 to 14 (mean = 2.9 ± 1.7). Ages at first and last pregnancy ranged from 16 to 44 years (mean = 24.9 ± 4.7) and 16 to 49 years (mean = 30.7 ± 5.5), respectively. Of 16 associations tested (4 pregnancy exposures by 4 cognitive tests), one was statistically significant without correction for multiple comparisons. Women who reported ever being pregnant recalled 0.12 fewer words on the Buschke Selective Reminding Test for every year increase in age than women who had never been pregnant (P = 0.05). No other significant associations of pregnancy history with cognitive decline were observed.

CONCLUSIONS

Our results show no clinically meaningful long-term influence of pregnancy history on age-related change in cognitive function. These reassuring findings suggest childbearing decisions and timing will not affect cognitive function in older age.

Gestational diabetes with diabetes and prediabetes risks: a large observational study

AIMS

To compare risks of early postpartum diabetes and prediabetes in Chinese women with and without gestational diabetes mellitus (GDM) during pregnancy.

SUBJECTS AND METHODS

Tianjin GDM observational study included 1263 women with a history of GDM and 705 women without GDM who participated in the urban GDM universal screening survey by using World Health Organization's criteria. Postpartum diabetes and prediabetes were identified after a standard oral glucose tolerance test. Cox proportional hazards regression was used to assess risks of postpartum diabetes and prediabetes between women with and without GDM.

RESULTS

During a mean follow-up of 3.53 years postpartum, 90 incident cases of diabetes and 599 incident cases of prediabetes were identified. Multivariable-adjusted hazard ratios among women with prior GDM, compared with those without it, were 76.1 (95% CI: 23.6-246) for diabetes and 25.4 (95% CI: 18.2-35.3) for prediabetes. When the mean follow-up extended to 4.40 years, 121 diabetes and 616 prediabetes cases were identified. Women with prior GDM had a 13.0-fold multivariable-adjusted risk (95% CI: 5.54-30.6) for diabetes and 2.15-fold risk (95% CI: 1.76-2.62) for prediabetes compared with women without GDM. The positive associations between GDM and the risks of postpartum diabetes and prediabetes were significant and persistent when stratified by younger and older than 30 years at delivery and normal weight and overweight participants.

CONCLUSIONS

The present study indicated that women with prior GDM had significantly increased risks for postpartum diabetes and prediabetes, with the highest risk at the first 3-4 years after delivery, compared with those without GDM.

Parity Increases Insulin Requirements in Pregnant Women With Type 1 Diabetes

CONTEXT

Tight glycemic control throughout pregnancy in women with type 1 diabetes is crucial, and knowledge about which factors that affect insulin sensitivity could improve the outcome for both mother and offspring.

OBJECTIVE

To evaluate insulin requirements in women with type 1 diabetes during pregnancy and test whether parity affects insulin requirements.

DESIGN

Observational cohort study consisting of women with type 1 diabetes who gave birth at Aarhus University Hospital, Denmark, from 2004 to 2014.

MAIN OUTCOME MEASURE

Daily insulin requirement (the hypothesis that parity could affect insulin resistance was formulated before data collection).

RESULTS

A total of 380 women with a total of 536 pregnancies were included in the study. Mean age was 31.1 years, and prepregnancy hemoglobin A1c was 60 mmol/mol. Parity was as follows: P0, 43%; P1, 40%; P2, 14%; and P3+4, 3%. Insulin requirements from weeks 11 to 16 decreased significantly by 4% (P = 0.0004) and rose from week 19 to delivery with a peak of 70% (P < 0.0005) at weeks 33 to 36. Overall, insulin requirements increased significantly with parity. The unadjusted differences between P0 and P1, P2, and P3+4 were 9% (P < 0.0005), 12% (P < 0.0005), and 23% (P < 0.0011), respectively. After adjustment for confounders, differences were 13% (P < 0.0005), 20% (P < 0.0005), and 36% (P < 0.0005). We also observed an adjusted difference between P1 and P3+4 of 20% (P < 0.0012).

CONCLUSIONS

The data show changes in insulin requirements from week to week in pregnancy and indicate that insulin requirements increase with parity. This suggests that the patient's parity probably should be considered in choosing insulin dosages for pregnant women with type 1 diabetes.

Associations between parity and maternal BMI in a population-based cohort study

INTRODUCTION

We aimed to investigate the change in prevalence of overweight and obesity in pregnant Danish women from 2004 to 2012, and investigate whether increasing parity was associated with a change in body mass index (BMI) prevalence.

MATERIAL AND METHODS

We obtained a population-based cohort from the Danish Medical Birth Registry consisting of all Danish women giving birth in 2004-2012 (n = 572 321). This registry contains information on 99.8% of all births in Denmark. We calculated the overall change in prepregnancy BMI status among pregnant women in Denmark, and a multiple linear regression model with adjustment for several potential confounders was used to examine the change in prepregnancy BMI with increasing parity.

RESULTS

In 2004, the prevalence of prepregnancy overweight and obesity (BMI ≥ 25) and obesity alone (BMI ≥ 30) was 31.9 and 11%, respectively. In 2012, the prevalence had reached 34.2 and 12.8%. The mean BMI increased for every additional parity from 23.80 (95% CI 23.77-23.82) in parity group 1 to 26.70 (26.52-26.90) in parity group 5+. A multiple linear regression adjusted for potential confounders showed that women on average gained 0.62 (0.58-0.65) BMI units after every additional birth.

CONCLUSIONS

This study showed a 7.2% increase in overweight and obesity (BMI ≥ 25) and a 16.4% increase in obesity alone (BMI ≥ 30) for pregnant women in Denmark from 2004 to 2012. In addition, an increase in interpregnancy BMI was seen at every additional delivery, suggesting that obesity is an increasing challenge in obstetrics.

Reproductive Investment and Health Costs in Roma Women

In this paper, we examine whether variation in reproductive investment affects the health of Roma women using a dataset collected through original anthropological fieldwork among Roma women in Serbia. Data were collected in 2014–2016 in several Roma semi-urban settlements in central Serbia. The sample consisted of 468 Roma women, averaging 44 years of age. We collected demographic data (age, school levels, socioeconomic status), risk behaviors (smoking and alcohol consumption), marital status, and reproductive history variables (the timing of reproduction, the intensity of reproduction, reproductive effort and investment after birth), in addition to self-reported health, height, and weight. Data analyses showed that somatic, short-term costs of reproduction were revealed in this population, while evolutionary, long-term costs were unobservable—contrariwise, Roma women in poor health contributed more to the gene pool of the next generation than their healthy counterparts. Our findings appear to be consistent with simple trade-off models that suggest inverse relationships between reproductive effort and health. Thus, personal sacrifice—poor health as an outcome—seems crucial for greater reproductive success.

Effect of multiparity and ethnicity on the risk of development of diabetes: a large population-based cohort study

AIMS

To investigate the relationship between increasing parity and diabetes in a large, population-based cohort, and to examine if this relationship is different among high-risk ethnic groups.

METHODS

A population-based, retrospective cohort study was performed in 738 440 women aged 18-50 years, who delivered babies in Ontario between 1 April 2002 and 31 March 2011. Diabetes incidence postpartum was calculated for each parity and ethnic group. A multivariable analysis of the effect of parity and ethnicity on the incidence of diabetes was performed using a Cox proportional hazards model, adjusting for confounders.

RESULTS

The diabetes incidence rate per 1000 person-years was 3.69 in women with 1 delivery, 4.12 in women with 3 deliveries and 7.62 in women with ≥5 deliveries. Women with ≥3 deliveries had a higher risk of developing diabetes compared with women with 1 delivery [adjusted hazard ratios 1.06 (95% CI 1.01-1.11) for 3 deliveries, 1.33 (95% CI 1.25-1.43) for 4 deliveries and 1.53 (95% CI 1.41-1.66) for ≥5 deliveries). A similar rise in risk could be seen in Chinese and South-Asian women, with the most influence in Chinese women [hazard ratio 4.59 (95% CI 2.36-8.92) for ≥5 deliveries].

CONCLUSIONS

There was a positive and graded relationship between increasing parity and risk of development of diabetes. The influence of parity was seen in all ethnicities. This association may be partly related to increasing weight gain and retention with increasing parity, or deterioration in β-cell function. This merits further exploration.

Parity, weight change, and maternal risk of cardiovascular events

BACKGROUND

High parity has been suggested to increase risk of maternal cardiovascular disease independent of body mass index measured after childbearing. Pregnancy is, however, associated with persistent weight gain and metabolic changes that, independent of parity, increase the risk of cardiovascular disease. It could therefore be questioned if high parity independently increases the risk of cardiovascular disease or if this association may be confounded, mediated, or modified by other parity-related factors.

OBJECTIVE

We sought to investigate the association between parity and risk of cardiovascular disease, and secondary outcomes in terms of myocardial infarction and cerebral infarction, with particular focus on potential mediation by anthropometric measures and effect modification by lactation.

STUDY DESIGN

We used data from 16,515 female participants (age 44.5-73.6 years) of the population-based Malmö Diet and Cancer Study with baseline examination from 1991 through 1996. The Malmö Diet and Cancer Study was followed up throughout 2010, with a median follow-up of 15.8 years. We used Cox proportional hazards model to examine the association between parity and cardiovascular disease.

RESULTS

Adjusted for age and other potential confounders, grand multiparous women (≥5 children) had an increased risk of cardiovascular disease (hazard ratio, 1.60; 95% confidence interval, 1.20-2.14), myocardial infarction (hazard ratio, 1.68; 95% confidence interval, 1.15-2.45), and cerebral infarction (hazard ratio, 1.74; 95% confidence interval, 1.18-2.58) compared to women with 2 children. Additional adjustment for baseline body mass index and weight change since age 20 years attenuated the risk, but the increased risk for cardiovascular disease (hazard ratio, 1.38; 95% confidence interval, 1.02-1.87) and myocardial infarction (hazard ratio, 1.53; 95% confidence interval, 1.04-2.26) in grand multiparous women remained significant. Models stratified by lactation time showed that risk was only raised in grand multiparous women who had a mean lactation time of <4 mo/child. In sensitivity analyses excluding women with a history of diabetes at baseline, risk estimates for grand multiparous women became nonsignificant in the full model.

CONCLUSION

Part of the increased risk of cardiovascular disease and myocardial infarction in grand multiparous women seems to be mediated by weight gain and potentially by higher likelihood of type 2 diabetes mellitus. Lactation may modify the increased risk of grand multiparity in that longer duration might offset the cardiovascular disease risk.

Higher parity is associated with increased risk of Type 2 diabetes mellitus in women: A linear dose-response meta-analysis of cohort studies

AIM

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.

METHODS

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.

RESULTS

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%, P_{heterogeneity}=0.002, Power=0.99). In the dose-response analysis, a noticeable linear dose-risk relation was found between parity and T2DM (P_{for 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%, P_{heterogeneity}=0.003, Power=0.99). Subgroup and sensitivity analyses yielded similar results. No publication bias was found in the results.

CONCLUSION

This meta-analysis suggests that higher parity and the risk of T2DM show a linear relationship in women.

MECHANISMS IN ENDOCRINOLOGY: Parity and risk of type 2 diabetes: a systematic review and dose-response meta-analysis

OBJECTIVE

Epidemiologic studies regarding the association between parity and risk of type 2 diabetes have yielded inconsistent results. Therefore, we performed a systematic review and dose-response meta-analysis to determine the relation between parity and type 2 diabetes risk.

METHODS

We searched PubMed and Embase for published epidemiologic studies that assessed the relation between parity and risk of type 2 diabetes up to 31 March 2016. A dose-response random-effects model was used to combine study-specific relative risks (RRs) and 95% confidence intervals (CIs). Potential sources of heterogeneity were explored by meta-regression and subgroup analyses.

RESULTS

Seven cohort studies, 1 case-control study and 9 cross-sectional studies including 296 923 participants were eligible for inclusion. The combined RR for the highest versus lowest category of parity indicated a 54% increment in type 2 diabetes risk (95% CI: 29-83%). In the cubic spline model, a nonlinear association was found between parity and risk of type 2 diabetes (P = 0.02 for nonlinearity). Compared with nulliparous women, the estimated RR (95% CI) of type 2 diabetes for women with one to seven children was 1.01 (0.96-1.07), 1.08 (1.00-1.16), 1.20 (1.12-1.30), 1.32 (1.22-1.42), 1.37 (1.27-1.48), 1.39 (1.26-1.52) and 1.39 (1.23-1.57) respectively.

CONCLUSIONS

Higher parity is significantly associated with an increased risk of type 2 diabetes. Further studies are warranted to fully adjust for the potential confounders and explore the causality between parity and type 2 diabetes risk.

Parenthood and the risk of diabetes in men and women: a 7 year prospective study of 0.5 million individuals

AIMS/HYPOTHESIS

In women, higher parity has been associated with increased risk of diabetes later in life. It is unclear, however, whether this association is mainly due to biological effects of childbearing, or to socioeconomic and lifestyle factors associated with childrearing. We assessed the association between number of children and diabetes risk separately in women and men.

METHODS

Between 2004 and 2008, the nationwide China Kadoorie Biobank recruited 0.5 million individuals aged 30-79 (mean 51 years) from ten diverse regions across China. During 7 years of follow-up, 8,840 incident cases of diabetes were recorded among 463,347 participants without prior cardiovascular diseases or diabetes. Multivariable Cox regression yielded sex-specific HRs and 95% CIs for incident diabetes by number of children.

RESULTS

Overall, ∼98% of all participants had children. In women, there was a J-shaped association between number of children and risk of diabetes. Compared with women with one child, the adjusted HRs for diabetes were 1.39 (95% CI 1.11, 1.73) for childless women, 1.12 (95% CI 1.07, 1.18) for those with two children, 1.23 (95% CI 1.16, 1.31) for those with three children, and 1.32 (95% CI 1.21, 1.44) for those with four or more children. In men, there was a similar association with risk of diabetes; the corresponding HRs were 1.28 (95% CI 1.02, 1.60), 1.19 (95% CI 1.12, 1.26), 1.32 (95% CI 1.21, 1.44) and 1.41 (95% CI 1.24, 1.60), respectively. In both sexes, the findings were broadly similar in different population subgroups.

CONCLUSIONS/INTERPRETATION

The similarity between women and men in the association between number of children and risk of diabetes suggests that parenthood is most likely to affect diabetes risk through factors associated with childrearing rather than via biological effects of childbearing.

Evidence for the Cost of Reproduction in Humans: High Lifetime Reproductive Effort Is Associated with Greater Oxidative Stress in Post-Menopausal Women

Life history theory predicts trade-offs between reproductive effort and maternal survivorship in energy-restricted environments. However, empirical evidence for the positive association between maternal mortality and reproductive effort from energetically challenged human populations are mixed and physiological mechanisms that may underlie this association are poorly understood. We hypothesized that increases in aerobic metabolism during repeated periods of pregnancy and lactation result in increased oxidative stress that may contribute to somatic deterioration, vulnerability to illness, and accelerated aging. We therefore predicted that lifetime gravidity and parity would be related to levels of biomarkers of oxidative stress, as well as antioxidative defence enzymes in post-menopausal women. Our hypothesis was supported by positive linear associations between levels of 8-OHdG, a biomarker of DNA oxidative damage (β = 0.21, p<0.05), levels of antioxidative defence enzyme Cu-Zn SOD (β = 0.25, p<0.05), and number of lifetime pregnancies. Furthermore, independent of age and health status, post-menopausal women with higher gravidity and parity (> = 4 pregnancies per lifetime) had 20% higher levels of 8-OHdG and 60% higher levels of Cu-Zn SOD compared to women with lower gravidity and parity (<4 pregnancies per lifetime). Our results present the first evidence for oxidative stress as a possible cost of reproductive effort in humans.

Parity and type 2 diabetes mellitus: a study of insulin resistance and β-cell function in women with multiple pregnancies

OBJECTIVE

Increasing parity may be a risk factor for the development of type 2 diabetes mellitus and the metabolic alterations during a normal pregnancy induces a prediabetic state; thus, multiple pregnancies may act as a risk factor for development of type 2 diabetes if these physiological alterations in glucose homeostasis are not reversed postpartum. We hypothesize that multiple pregnancies may lead to β-cell exhaustion and that the insulin resistance that occurs during pregnancy may persist after multiple births.

RESEARCH DESIGN AND MEASURES

A total of 28 healthy premenopausal women were recruited: 15 high parity women (≥4 children) and 13 body mass index (BMI)-matched and age-matched low parity women (1 and 2 children). The study consisted of an intravenous glucose tolerance test for assessment of β-cell function followed by a hyperinsulinemic euglycemic clamp for assessment of insulin sensitivity. Dual-energy X-ray absorptiometry was performed to assess body composition.

RESULTS

All anthropometric measures, measures of body composition and baseline blood samples were comparable between the 2 groups. Neither first phase insulin release (0-10 min, p=0.92) nor second phase insulin release (10-60 min, p=0.62), both measured as area under the curve, differed between the 2 groups. The M-value, calculated as the mean glucose infusion rate during the last 30 min of the clamp period, was 8.66 (7.70 to 9.63) mg/kg/min in the high parity group compared with 8.41 (7.43 to 9.39) mg/kg/min in the low parity group (p=0.69).

CONCLUSIONS

We did not detect any effects of increasing parity on insulin sensitivity or β-cell function.

Risk of breast cancer by individual insulin use: an international multicenter study

OBJECTIVE Several studies have been published in 2009 suggesting a possible association between insulin glargine and increased risk of malignancies, including breast cancer. The objective of this study was to assess the relation between the individual insulins (glargine, aspart, lispro, and human insulin) and development of breast cancer. RESEARCH DESIGN AND METHODS Seven hundred seventy-five incident cases of primary invasive or in situ carcinoma breast cancer occurring in women with diabetes from 92 centers in the U.K., Canada, and France were matched to a mean of 3.9 diabetic community control subjects (n = 3,050; recruited from 580 general practices) by country, age, recruitment date, and diabetes type and management. The main risk model was a multivariate conditional logistic regression model with case/control status as the dependent variable and individual insulin use, 8 years preceding the index date, as the independent variable, controlling for past use of any insulin, oral antidiabetes drugs, reproductive factors, lifestyle, education, hormone replacement therapy and history of contraceptive use, BMI, comorbidities, diabetes duration, and annual number of physician visits. Glargine was also compared with every other insulin by computing all ratios using the variance-covariance matrix of logistic model parameters. RESULTS Adjusted odds ratios of breast cancer for each type of insulin versus no use of that insulin were 1.04 (95% CI 0.76-1.44) for glargine, 1.23 (0.79-1.92) for lispro, 0.95 (0.64-1.40) for aspart, and 0.81 (0.55-1.20) for human insulin. Two-by-two comparisons found no difference between glargine and the different types of insulins. Insulin dosage or duration of use and tumor stage did not change the results. CONCLUSIONS This international study found no difference in the risk of developing breast cancer in patients with diabetes among the different types of insulin with short- to mid-term duration of use. Longer-term studies would be of interest.

Offspring preterm birth and birth size are related to long-term risk of maternal diabetes

The aim of the study is to investigate the association between gestational age, birth size, and the long-term risk of maternal diabetes. We conducted a nation-wide prospective follow-up study of the cohort of all Danish women with a singleton delivery in 1982/1983 (index delivery) and no history of diabetes (n = 100,669). Registries were used to extract information on patients with a hospital or outpatient diagnosis of diabetes, subsequent deliveries, and death/emigration in the period from the index delivery until the end of 2006. The association between the maternal risk of diabetes and the index gestational age and index offspring birth size (birth weight adjusted for gestational age) was investigated by using Cox proportional hazards regression models stratified according to young (≤33 years) and old age (>33 years). During a median follow-up period of 24 years, 2,021 women (2.0 %) were diagnosed as having diabetes. The risk of maternal diabetes was positively associated with increasing index birth size and negatively associated with increasing duration of index gestation in both age strata. Among young women, the highest hazard ratios were found for the exposure category of large index offspring birth size (adjusted HR 9.0, 95 % CI 6.17-13.12) and a preterm delivery at 32-37 weeks (adjusted HR 2.22, 95 % CI 1.46-3.40). Offspring preterm birth and large size for gestational age at birth are associated with increased risk of maternal diabetes.

Gestational diabetes and future risk of diabetes

BACKGROUND

In this study of women with gestational diabetes we attempted to (a) Determine the magnitude of the long term risk of progression to diabetes and (b) Identify factors that predict the development of diabetes.

METHODS

All women diagnosed with gestational diabetes (GDM) at Worcestershire Royal Hospital, UK from 1995 to 2003 were included in this observational cohort study and followed up till 2009. Diabetes was diagnosed if fasting glucose ≥ 7.0 mmol/L, random/two-hour glucose following 75 gram oral glucose test (OGTT) ≥ 11.1 mmol/L or HbA1c ≥ 7.0%.

RESULTS

The risk of developing diabetes was 6.9% at five years and 21.1% at ten years following the initial diagnosis of GDM. Fasting and post-prandial glucose levels in the oral glucose tolerance test during pregnancy were associated with future risk of diabetes. There was no association with age, gestational age at diagnosis of GDM, numbers of previous and subsequent pregnancies.

CONCLUSION

Risk of progression to diabetes in a UK based cohort of women with GDM is estimated. Women with fasting antenatal glucose ≥ 7.0 mmol/L and/or an antenatal two-hour glucose ≥ 11.1 mmol/L are at higher risk and need close follow up.

Changes of insulin resistance and β-cell function in women with gestational diabetes mellitus and normal pregnant women during mid- and late pregnant period: a case-control study

AIM

The aim of this study was to observe insulin resistance and β-cell function changes among women diagnosed with gestational impaired glucose tolerance or gestational diabetes mellitus (GDM) in mid-pregnancy.

MATERIAL AND METHODS

Sixty-four pregnant women receiving prenatal care underwent an oral glucose tolerance test at 20-24 weeks of gestation and an insulin release test. The GDM group included 34 pregnant women diagnosed with gestational impaired glucose tolerance or GDM, and the subjects with normal blood glucose were the control group. Insulin resistance and islet β-cell function changes were observed with the oral glucose tolerance test and insulin release test.

RESULTS

The homeostatic model assessment-β levels in late pregnancy were higher than those in mid-pregnancy for both groups, and the primary time effect was statistically significant. The early insulin secretion index (ΔI(30)/ΔG(30)) values in mid- and late pregnancy were lower in the GDM group. The values of the area under the curve of blood glucose in mid- and late pregnancy were higher in the GDM group than those in the control group. Insulin resistance was higher in GDM patients than in normal pregnant women.

CONCLUSIONS

Insulin resistance was aggravated, and β-cell's ability to compensate for the increased insulin resistance by modulating insulin secretion was aggravated, as gestational week increased in women with gestational diabetes and normal pregnant women. Insulin resistance in women with GDM is higher than in pregnant women with normal metabolism of glucose.

Number of children and change in markers of metabolic health over 9-years in men and women. Data from the DESIR study

AIM

Parity is associated with an increased risk of coronary heart disease and type 2 diabetes, possibly mediated by long-term modification of metabolic health. Studying associations between the number of children with health and disease in men in addition to women allows for differentiation between the social and lifestyle influences of child-rearing, and the biological influences of childbearing. We sought to determine whether the number of children is associated with the incidence of raised fasting glucose (fasting plasma glucose≥6.1 mmol/L) and changes in glucose, insulin, insulin resistance and β-cell function over 9-years.

METHODS

Analysis of 1798 women and 1737 men from the DESIR study.

RESULTS

The number of children was associated with change in fasting glucose for women (P(trend)=0.02) and men (P(trend)=0.03), and increased incidence of raised fasting glucose by 30% (95% CI: 15, 47%) per child for men, but not women (3% [95% CI: -8, 15%]). There was a J-shaped association between number of children and change in insulin (P=0.01) and insulin resistance (P=0.005) for women, and a reduction in β-cell function in parous women (P=0.07). Men with children had increases in insulin (P=0.02), insulin resistance (P=0.02), and β-cell function (P=0.07).

CONCLUSIONS

The number of children a person has is associated with changes in metabolic health indices long after childbirth for both men and women. The distinct gender differences in deterioration of metabolic health indices emphasize that childbearing and child-rearing are likely to have differential influences on metabolic health.