Tall or short? Twenty years after preeclampsia exposure in utero: comparisons of final height, body mass index, waist-to-hip ratio, and age at menarche among women, exposed and unexposed to preeclampsia during fetal life

Short- and Long-Term Outcomes of Preeclampsia in Offspring: Review of the Literature

Preeclampsia is a multisystemic clinical syndrome characterized by the appearance of new-onset hypertension and proteinuria or hypertension and end organ dysfunction even without proteinuria after 20 weeks of pregnancy or postpartum. Residing at the severe end of the spectrum of the hypertensive disorders of pregnancy, preeclampsia occurs in 3 to 8% of pregnancies worldwide and is a major cause of maternal and perinatal morbidity and mortality, accounting for 8-10% of all preterm births. The mechanism whereby preeclampsia increases the risk of the neurodevelopmental, cardiovascular, and metabolic morbidity of the mother's offspring is not well known, but it is possible that the preeclamptic environment induces epigenetic changes that adversely affect developmental plasticity. These developmental changes are crucial for optimal fetal growth and survival but may lead to an increased risk of chronic morbidity in childhood and even later in life. The aim of this review is to summarize both the short- and long-term effects of preeclampsia on offspring based on the current literature.

Effect of hypertensive disorders of pregnancy on pubertal development in daughters and sons: a systematic review and meta-analysis

Hypertensive disorders of pregnancy (HDP) are a major cause of maternal and offspring morbidity and mortality worldwide. Several studies in recent years have focused on the link between HDP and pubertal development in offspring. The goal of this study was to synthesize the published literature on the effect of HDP on pubertal development in offspring by a systematic review and meta-analysis (PROSPERO 2021: CRD42020148736). A systematic literature search of several databases was conducted through December 2021, focusing on studies reporting pubertal development in offspring of women with and without HDP exposure. Primary outcomes of interest included offspring body mass index (BMI), height, waist and hip circumference, fat mass, pubarche, thelarche, and age at menarche. A total of 21 studies were finally included. Significantly higher values of BMI (SMD: 0.16 [0.11, 0.22]; p < 0.01) and waist circumference (SMD: 0.21 [0.14, 0.29]; p < 0.01) were found in offspring exposed to maternal HDP. In addition, a tendency of the early development of secondary sexual characteristics only in daughters was presented in offspring whose mothers were diagnosed with HDP. The findings imply a possible effect of HDP on pubertal development in offspring, especially for their BMI and waist circumference, which highlights the importance of focusing on adolescent developmental abnormalities in offspring exposed to HDP.

Association of hypertensive disorders of pregnancy with infant growth in the first 36 months of life

To investigate the association of chronic hypertension, gestational hypertension, and preeclampsia diseases with infant growth in the first 36 months of life, we conducted a retrospective birth cohort of 31,734 children born in Zhoushan Maternal and Child Care Hospital between January 2001 and May 2018. Birthweight, gestational age, and infant growth (weight, height, weight/height-for-age Z score, the weight gain during childhood) were the main outcomes. The associations of chronic hypertension, gestational hypertension, and preeclampsia diseases with birth outcomes and infant growth at children's age of 3, 6, 12, 18, and 24 months were analyzed by multivariable regression models. Gestational hypertension, preeclampsia diseases, and chronic hypertension were significantly associated with lower birthweight and shorter gestational age. Both gestational hypertension and preeclampsia diseases were respectively inversely associated with weight, weight-for-age Z score, height, and height-for-age Z score of children in the whole sample and sub-sample data analysis from birth to the age of 36 months, although correction for birthweight rendered the associations nonsignificant. No significant association of gestational hypertension, preeclampsia diseases, and chronic hypertension with weight gain was found. Conclusion: The inverse associations of gestational hypertension and preeclampsia diseases with infant growth in early childhood were mainly mediated by the effect of gestational hypertension and preeclampsia diseases on lower birthweight. What is Known: • Hypertensive disorders of pregnancy are associated with increased risk of adverse birth outcomes. What is New: • Both gestational hypertension and preeclampsia were respectively inversely associated with physical development of offspring from birth to the age of 36 months. • Lower birthweight might be the mediator of the inverse associations of gestational hypertension and preeclampsia diseases with infant growth in early childhood.

Association of gestational hypertension and preeclampsia with offspring adiposity: A systematic review and meta-analysis

BACKGROUND

The association of gestational hypertension (GH) and preeclampsia (PE) with offspring adiposity outcomes had controversial results in different studies.

OBJECTIVE

We conducted a systematic review and meta-analysis to evaluate the relationship between maternal GH/PE and offspring adiposity outcomes.

SEARCH STRATEGY

Studies were identified in PubMed, Embase, and Cochrane databases, with keywords including "gestational hypertension", "preeclampsia", "offspring", "weight", "cohort study", etc., without year restriction. This study was registered with PROSPERO, CRD42022292084.

SELECTION CRITERIA

We set the selection criteria for six aspects: population, outcome, time frame, study design, and availability. For the studies included in the meta-analysis, we required the potential confounders in these studies have been adjusted.

DATA COLLECTION AND ANALYSIS

Two reviewers independently evaluated the data from the included studies. The meta-analyses included mean differences, regression coefficients, and corresponding 95% confidence intervals. Results were performed using RevMan software (version 5.4; Cochrane Collaboration). Heterogeneity among the included studies was assessed using the I² statistic.

MAIN RESULTS

A total of 16 studies were included in our review, 15 of which were evaluated as high quality. In all offspring, during the early life (28 days-36 months), GH/PE exposure was found to be not or inversely associated with offspring obesity, then become positively associated at larger ages (3-19 years old). In offspring with adverse birth outcomes, the maternal GH/PE-exposed group had a lower weight in the short term (28 days to 18 months), but there was a trend of rapid weight gain as they grew older, compared with the non-exposed group. The meta-analysis showed that the BMI of the female offspring in the maternal PE-exposed group was significantly higher than that of the non-exposed offspring (MD=1.04, 95% CI: 0.67~1.42, P < 0.05).

CONCLUSIONS

The systematic review suggested that maternal exposure to de novo hypertension disorders of pregnancy (HDP) was associated with obesity in offspring, extending from early childhood to adolescence. The meta-analysis showed that PE was associated with higher BMI in female offspring. More studies are needed to conduct stratified analyses by PE/GH, the severity of HDP, or gender.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, identifier CRD42022292084.

Hypertensive Disorders during Pregnancy and Anthropometric Measurement of Children up to 7 Years of Age: The Hokkaido Birth Cohort Study in Japan

Hypertensive disorders during pregnancy (HDP) increase the risk of offspring with a low birth weight, preterm birth and small-for-gestational age; however, evidence of the anthropometric measurements during early childhood remains limited. We aimed to understand the associations between maternal HDP and anthropometric measurements of children aged up to seven years in a Japanese cohort. In total, 20,926 mother–infant pairs participated in the Hokkaido Study on Environment and Children’s Health, Japan, from 2002 to 2013. Medical reports were used to confirm HDP exposure, while weight, height, height z score, and weight z score were the outcomes. The prevalence of HDP in the study population was 1.7%. The birth height of male children born to HDP mothers was smaller as compared to those born to non-HDP mothers. When adjusted with covariates, the linear regressions showed significant changes in birth weight (β: −79.3; 95% confidence interval [CI]: −154.8, −3.8), birth height (−0.67; 95% CI: −1.07, −0.26), weight at seven years (1.21; 95% CI: 0.13, 2.29), and weight gain between four and seven years (1.12; 95% CI: 0.28, 1.96) of male children exposed to HDP. Differences were more significant in male children than female. Our study showed that despite low birth weight, male children exposed to HDP caught up with their growth and gained more weight by seven years of age compared with male children not exposed to HDP, whereas no such differences were observed in female children; however, this finding requires replication.

Hypertensive disorders in pregnancy and timing of pubertal development in daughters and sons

STUDY QUESTION

Do maternal hypertensive disorders affect pubertal development in daughters and sons?

SUMMARY ANSWER

Pubertal development tended to occur earlier in daughters of mothers with 'preeclampsia, eclampsia or HELLP syndrome' (hemolysis, elevated liver enzymes and low blood platelets) or hypertension in pregnancy compared to daughters born of normotensive mothers.

WHAT IS KNOWN ALREADY

The existing literature suggests some or no association between preeclampsia and pubertal development in daughters, but not in sons. None of the previous studies has investigated the possible association between other types of hypertensive disorders (hypertension, eclampsia or HELLP syndrome) and pubertal timing in children.

STUDY DESIGN, SIZE, DURATION

Longitudinal cohort study consisting of 15 819 mother-child pairs with information on maternal hypertensive disorders collected during pregnancy and information on pubertal development collected half-yearly from the age of 11 years and until fully developed or 18 years of age.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants are children from the Puberty Cohort nested within the Danish National Birth Cohort. The exposure was register-based and self-reported information on maternal hypertensive disorders during pregnancy. The outcomes were children's self-reported information on pubertal development, including Tanner stage 1-5 (pubic hair (both daughters and sons) and breast development (daughters) or genital development (sons)), first menstrual bleeding (daughters) or first ejaculation (sons), voice break episode (sons), axillary hair development and acne occurrence (both daughters and sons). The main outcome was mean difference in age at attaining each pubertal milestone and a combined pubertal marker in children of mothers with hypertensive disorders in pregnancy (either hypertension (n = 490), 'preeclampsia, eclampsia or HELLP syndrome' (n = 419) or 'unspecific hypertensive disorders' (n = 334) with unexposed children as reference (n = 14 576)).

MAIN RESULTS AND THE ROLE OF CHANCE

In daughters of mothers with 'preeclampsia, eclampsia or HELLP syndrome', we observed tendencies of earlier pubertal timing (combined marker: -2.0 (95% CI: -3.9; 0.0) months). In daughters of mothers with hypertension, several pubertal milestones tended to occur earlier than in daughters of normotensive mothers; however, all 95% CIs overlapped the null resulting in a combined pubertal marker of -1.0 (95% CI: -3.2; 1.1) months. In sons of mothers with any of the hypertensive disorders, we observed no difference in pubertal timing (combined markers: 'preeclampsia, eclampsia or HELLP syndrome': 0.1 (95% CI: -2.0; 2.1) months; hypertension: -0.6 (95% CI: -2.3; 1.1) months; 'unspecific hypertensive disorders': 0.2 (95% CI: -1.9; 2.2) months).

LIMITATIONS, REASONS FOR CAUTION

The study is subject to non-differential misclassification of self-reported information on maternal hypertensive disorders in pregnancy and current pubertal status; possibly causing bias toward the null.

WIDER IMPLICATIONS OF THE FINDINGS

Hypertensive disorders in pregnancy might accelerate pubertal timing in daughters; however, more studies are needed for causal conclusions.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Faculty of Health at Aarhus University. The authors have no financial relationships or competing interests to disclose.

TRIAL REGISTRATION NUMBER

N/A.

Association of preeclampsia with anthropometric measures and blood pressure in Indian children

BACKGROUND AND OBJECTIVE

Birth weight and post-natal growth are important predictors of adult health. Preeclampsia (PE) is associated with low birth weight and may have long term effects on the health of the children. The current study aims to compare anthropometry and blood pressure between children of mothers with and without PE in an Indian cohort.

METHODS

We studied children born to women with (PE; n = 211) and without preeclampsia (non-PE; n = 470) at Bharati Hospital, Pune, India. Anthropometry and blood pressure were measured in children at 3-7 years of age. Weight and height Z-scores were calculated using the WHO 2006 growth reference. Independent t-tests were used to compare means between the two groups, and associations between preeclampsia and child outcomes were analyzed using multiple linear regression, adjusting for potential confounders.

RESULTS

Weight and height Z-scores (p = 0.04 and 0.008), and subscapular skinfold thickness (p = 0.03) were higher among children of PE compared with children of non-PE mothers. Systolic blood pressure was also higher in children of PE mothers (1.70 mmHg [95% CI 0.05, 2.90] p = 0.006). BMI and diastolic blood pressure did not differ between groups. In regression models adjusted for newborn weight and gestational age, current age and sex, and maternal height, BMI and socio-economic status, children of PE mothers had higher weight Z-score (0.27 SD [95%CI 0.06, 0.48] p = 0.01), height Z-score (0.28 SD [95%CI 0.09, 0.47] p = 0.005), and subscapular skinfold thickness (0.38 mm [95%CI 0.00, 0.76] p = 0.049). A trend for higher systolic blood pressure (1.59 mmHg [95%CI -0.02, 3.20] p = 0.053) in the children was also observed in the adjusted model. The difference in systolic blood pressure was attenuated after adjusting further for the child's weight and height (1.09 mmHg [95%CI -0.48, 2.67] p = 0.17). There was no evidence of differences in effects between boys and girls.

CONCLUSION

Children of PE mothers were taller and heavier, and had higher systolic blood pressure, partly explained by their increased body size, than children of non-PE mothers. In utero exposure to preeclampsia may increase the risk of future cardiovascular disease.

Preeclampsia exposed offspring have greater body mass index than non-exposed offspring during peripubertal life: A meta-analysis

BACKGROUND

This study evaluates the effect of preeclampsia on body mass index (BMI) of offspring who were exposed to preeclampsia in utero.

METHODS

Data were obtained from studies identified by a literature search in electronic databases. Random-effects metanalyses were conducted to achieve mean difference in BMI, waist circumference, gestation length, and birthweight between preeclampsia exposed (PE) and non-exposed (non-PE) offspring older than 5 years. Metaregression analyses were performed to identify factors affecting offspring BMI.

RESULTS

Sixteen studies (11639 PE offspring; age 15.5 years [14.2, 16.8]; 33.3% [32.6, 33.9] males vs 526,576 non-PE offspring; age 15.7 years [15.0, 16.4]; 42.6% [40.6, 44.5] male) were used. Gestation duration and birthweight of PE fetuses were significantly lesser than those of non-PE fetuses (mean difference (MD) -0.66 weeks [-1.25, -0.07]; p = 0.03 and MD -207.9 [-344.0, -71.8]; p = 0.003) respectively. BMI of PE offspring was significantly higher than non-PE offspring (MD 0.54 kg/m² [0.27, 0.82]; p = 0.0001). Odds of being obese was significantly higher in PE than non-PE offspring (odds ratio 2.12 [1.70, 2.66]; P < 0.00001). Waist circumference was also significantly higher in PE than in non-PE offspring (MD 1.37 cm [0.67, 2.06]; p = 0.0001). Offspring BMI was significantly inversely associated with maternal age in both PE and non-PE groups.

CONCLUSION

Preeclampsia poses risk of higher BMI and waist circumference especially to the offspring of older mothers.

Prenatal exposure to preeclampsia is associated with accelerated height gain in early childhood

Background

Preeclampsia is associated with low birth weight, both because of increased risks of preterm and of small-for-gestational-age (SGA) births. Low birth weight is associated with accelerated childhood height gain and cardiovascular diseases later in life. The aim was to investigate if prenatal exposure to preeclampsia is associated with accelerated childhood height gain, also after adjustments for SGA-status and gestational age at birth.

Methods

In a cohort of children prenatally exposed to preeclampsia (n = 865) or unexposed (n = 22,898) we estimated height gain between birth and five years of age. The mean difference in height gain between exposed and unexposed children was calculated and adjustments were done with linear regression models.

Results

Children exposed to preeclampsia were on average born shorter than unexposed. Exposed children grew on average two cm more than unexposed from birth to five years of age. After adjustments for maternal characteristics including socioeconomic factors, height, body mass index (BMI) and diabetes, as well as for parents smoking habits, infant’s breastfeeding and childhood obesity, the difference was 1.6 cm (95% CI 1.3–1.9 cm). Further adjustment for SGA birth only slightly attenuated this estimate, but adjustment for gestational age at birth decreased the estimate to 0.5 cm (95% CI 0.1–0.7 cm).

Conclusion

Prenatal exposure to preeclampsia is associated with accelerated height gain in early childhood. The association seemed independent on SGA-status, but partly related to shorter gestational age at birth.

A potential pathophysiological role for galectins and the renin-angiotensin system in preeclampsia

This review discusses a potential role of galectins and the renin-angiotensin system (RAS) in the pathophysiology of preeclampsia (PE). Preeclampsia affects between 3 and 5 % of all pregnancies and is a heterogeneous disease, which may be caused by multiple factors. The only cure is the delivery of the placenta, which may result in a premature delivery and baby. Probably due to its heterogeneity, PE studies in human have hitherto only led to the identification of a limited number of factors involved in the pathogenesis of the disease. Animal models, particularly in mice and rats, have been used to gain further insight into the molecular pathology behind PE. In this review, we discuss the picture emerging from human and animal studies pointing to galectins and the RAS being associated with the PE syndrome and affecting a broad range of cellular signaling components. Moreover, we review the epidemiological evidence for PE increasing the risk of future cardiovascular disease later in life.

Nongenetic determinants of age at menarche: a systematic review

BACKGROUND

The acceleration of pubertal development is an important medical and social problem, as it may result in increased morbidity and mortality in later life. This systematic review summarizes relevant data about nongenetic factors, which contribute to age at menarche (AAM), and suggests those which may be the most important.

METHODS

The available literature from 1980 till July 2013 was searched using PubMed and Google Scholar databases. Finally, 154 papers were selected for the analysis.

RESULTS

Environmental factors, which may affect AAM, vary in populations of different ethnicity. The prenatal, infancy, and early childhood periods are the most susceptible to these factors. Body weight, high animal protein intake, family stressors (e.g., single parenting), and physical activity seem to influence AAM in most populations.

CONCLUSIONS

The data about influence of nongenetic factors on AAM are still inconsistent. The factors affecting prenatal and early childhood growth seem to have a larger effect on further sexual maturation. Further studies are needed in order to validate the association between other environmental determinants and AAM in different ethnical groups.

Mode of delivery and offspring body mass index, overweight and obesity in adult life: a systematic review and meta-analysis

Background

It has been suggested that mode of delivery, a potentially powerful influence upon long-term health, may affect later life body mass index (BMI). We conducted a systematic review and meta-analysis of the effect of Caesarean section (CS) and vaginal delivery (VD) on offspring BMI, overweight (BMI>25) and obesity (BMI>30) in adulthood. Secondary outcomes were subgroup analyses by gender and type of CS (in-labour/emergency, pre-labour/elective).

Methods

Using a predefined search strategy, Pubmed, Google Scholar and Web of Science were searched for any article published before 31^st March 2012, along with references of any studies deemed relevant. Studies were selected if they reported birth characteristics and long-term offspring follow-up into adulthood. Aggregate data from relevant studies were extracted onto a pre-piloted data table. A random-effects meta-analysis was carried out in RevMan5. Results are illustrated using forest plots and funnel plots, and presented as mean differences or odds ratios (OR) and 95% confidence intervals.

Results

Thirty-five studies were identified through the search, and 15 studies with a combined population of 163,753 were suitable for inclusion in the meta-analysis. Comparing all CS to VD in pooled-gender unadjusted analyses, mean BMI difference was 0·44 kg·m^-2 (0·17, 0·72; p = 0·002), OR for incidence of overweight was 1·26 (1·16, 1·38; p<0·00001) and OR for incidence of obesity was 1·22 (1·05, 1·42; p = 0·01). Heterogeneity was low in all primary analyses. Similar results were found in gender-specific subgroup analyses. Subgroup analyses comparing type of CS to VD showed no significant impact on any outcome.

Conclusions

There is a strong association between CS and increased offspring BMI, overweight and obesity in adulthood. Given the rising CS rate worldwide there is a need to determine whether this is causal, or reflective of confounding influences.

Systematic review registration

An a priori protocol was registered on PROSPERO (registration number: CRD42011001851)

Size at birth and abdominal adiposity in adults: a systematic review and meta-analysis

We performed a systematic literature review on the associations between birth size and abdominal adiposity in adults, while also investigating the role of the adjustment for adult body mass index (BMI). MEDLINE, Scopus, Web of Science, LILACS and SciELO databases were searched for articles published up to February 2013. Only prospective studies were included. After screening 2,570 titles, we selected 31 publications for the narrative synthesis, of which 13 were considered to be of high methodological quality. Six main indicators of birth size were identified, and birth weight (BW) was the most extensively studied. Most studies relied on anthropometric measurements as proxies for abdominal fatness or as indicators of body fat distribution. Few studies assessed abdominal adiposity through imaging methods, generally with small sample sizes. Eleven articles could be included in the meta-analyses. BW was found to be positively associated with waist circumference in adulthood, but the association disappeared after adjustment for adult BMI. In contrast, there was no association between BW and waist-to-hip ratio, whereas a strong negative association became evident after controlling for adult BMI. In conclusion, BW seems to be associated with larger adult size in general, including both waist and hip circumferences. The marked change in coefficients after adjustment for adult BMI suggests that post-natal growth strongly affects relative central adiposity, whereas BW per se does not play a role. Given the potential impact of post-natal growth, further research is needed to identify different growth trajectories that lead to abdominal adiposity, as well as studies on interactions of foetal and post-natal growth patterns.

Prenatal and infant exposures and age at menarche

BACKGROUND

Early menarche is related to increased risk of breast cancer. The number of established factors that contribute to early menarche is limited. We studied prenatal and infant exposures in relation to age at menarche in a nationwide cohort of women who have a family history of breast cancer.

METHODS

The study comprised 33,501 women in the Sister Study who were 35-59 years of age at baseline (2003-2009). We used polytomous logistic regression to estimate separate relative risk ratios (rRRs) and 95% confidence intervals (CIs) for associations of self-reported exposures with menarche at ≤10, 11, 14, and ≥15 years relative to menarche at 12-13 years.

RESULTS

Early menarche (≤10 or 11 years) was associated with having low birth weight, having had a teenage mother, being firstborn, and specific prenatal exposures: mother's smoking, diethylstilbestrol (DES), prepregnancy diabetes, and pregnancy-related hypertensive disorder. Prenatal exposures most strongly associated with very early menarche (≤10 years) were DES (rRR = 1.56 [95% CI = 1.24-1.96]), maternal prepregnancy diabetes (2.24 [1.37-3.68]), and pregnancy-related hypertensive disorder (1.45 [1.18-1.79]). Soy formula was associated with both very early menarche (1.21 [0.94-1.54]) and late menarche (14 years: 1.17 [0.98-1.40] or ≥15 years: 1.28 [1.06-1.56]).

CONCLUSIONS

Although menarche is only one marker of pubertal development, it is a commonly used surrogate. The observed associations of prenatal DES and soy formula exposure with age at menarche are consistent with animal data on exogenous estrogens and pubertal timing. Early-life exposures may confound associations between age at menarche and hormonally dependent outcomes in adults.

Methylation levels at IGF2 and GNAS DMRs in infants born to preeclamptic pregnancies

Background

Offspring of pregnancy complicated with preeclampsia are at high risk for hypertension, stroke and possibly obesity. The mechanisms behind the association of intrauterine exposure to preeclampsia and high risk of health problems in the later life remain largely unknown. The aims of the current investigation were to determine the changes in DNA methylation at IGF2 and GNAS DMR in offspring of preeclamptic pregnancy and to explore the possible mechanisms underlying the association between maternal preeclampsia and high risk for health problems in the later life of their offspring.

Results

Umbilical cord blood was taken from infants born to women of preeclampsia (n=56), gestational hypertension (n=23) and normal pregnancy (n=81). DNA methylation levels of IGF2 and GNAS DMR were determined by Massarray quantitative methylation analysis. Methylation levels at IGF2 DMR were significantly lower in preeclampsia than normal pregnancy. The average methylation level at IGF2 DMR was significantly correlated with preeclampsia even after birth weight, maternal age, gestational age at delivery and fetal gender were adjusted. The difference in methylation level was not significantly different between mild and severe preeclampsia. The methylation level at GNAS DMR was not significantly correlated with birth weight, maternal age, gestational age at delivery, fetal gender, preeclampsia or gestational hypertension.

Conclusions

We concluded preeclampsia induced a decrease in methylation level at IGF 2 DMR, and this might be among the mechanisms behind the association between intrauterine exposure to preeclampsia and high risk for metabolic diseases in the later life of the infants.

What is in our environment that effects puberty?

Recent studies indicate that the onset of puberty is occurring at increasingly younger ages. Many etiologies have been hypothesized to be involved, but environmental exposures are among the most worrisome. Multiple organizations have endorsed the need to study and provide clinical awareness regarding the effect of a child's environment on pubertal timing. This review article summarizes the current understanding of the major environmental influences on pubertal timing, focusing on factors for which the most scientific evidence exists. The research reviewed addresses intrinsic factors unique to each individual, naturally occurring endocrine disruptors and chemical endocrine disruptors. In each category, evidence was found for and against the involvement of specific environmental factors on pubertal timing. Ultimately, an individual's environment is likely comprised of many aspects that collectively contribute to the timing of puberty. The need for research aimed at elucidating the effects of numerous specific yet disparate forms of exposures is emphasized.

Early markers of adult obesity: a review

The purpose of this review was to evaluate factors in early childhood (≤5 years of age) that are the most significant predictors of the development of obesity in adulthood. Factors of interest included exposures/insults in the prenatal period, infancy and early childhood, as well as other socio-demographic variables such as socioeconomic status (SES) or birth place that could impact all three time periods. An extensive electronic and systematic search initially resulted in 8,880 citations, after duplicates were removed. Specific inclusion and exclusion criteria were set, and following two screening processes, 135 studies were retained for detailed abstraction and analysis. A total of 42 variables were associated with obesity in adulthood; however, of these, only seven variables may be considered as potential early markers of obesity based on the reported associations. Possible early markers of obesity included maternal smoking and maternal weight gain during pregnancy. Probable early markers of obesity included maternal body mass index, childhood growth patterns (early rapid growth and early adiposity rebound), childhood obesity and father's employment (a proxy measure for SES in many studies). Health promotion programmes/agencies should consider these factors as reasonable targets to reduce the risk of adult obesity.

Are Twins at Risk of Cancer: Results From the Swedish Family-Cancer Database

A few twin studies on cancer have addressed questions on the possible carcinogenic or protective effects of twining by comparing the occurrence of cancer in twins and singletons. The nationwide Swedish Family-Cancer Database of 10.2 million individuals and 69,654 0- to 70-year-old twin pairs were used to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for all main cancers compared to singletons. The overall risk of cancer in same- or different-sex twins was at the same level as the risk for singletons. Testicular cancer, particularly seminoma, was increased among same-sex twins (1.54) and all twins to an SIR of 1.38. Among other tumors, neurinomas and nonthyroid endocrine gland tumors were increased. Colorectal cancers and leukemia were decreased among all twins. Melanoma and squamous cell skin cancer were decreased in male same-sex twins. The data on this unselected population of twins suggest that twinning per se is not a risk factor of cancer. In utero hormonal exposures or postnatal growth stimulation may be related to the risk of testicular cancer and pituitary tumors. Protective effects against colorectal cancer may be related to a beneficial diet, and in melanoma and skin cancer, to socioeconomic factors. The study involved multiple comparisons, and internal consistency between the results was one of the main factors considered for their plausibility. The results should encourage others working on twin and singleton populations to examine the specific associations and emerging hypotheses.

Early markers of adult obesity: a review

The purpose of this review was to evaluate factors in early childhood (≤5 years of age) that are the most significant predictors of the development of obesity in adulthood. Factors of interest included exposures/insults in the prenatal period, infancy and early childhood, as well as other socio-demographic variables such as socioeconomic status (SES) or birth place that could impact all three time periods. An extensive electronic and systematic search initially resulted in 8,880 citations, after duplicates were removed. Specific inclusion and exclusion criteria were set, and following two screening processes, 135 studies were retained for detailed abstraction and analysis. A total of 42 variables were associated with obesity in adulthood; however, of these, only seven variables may be considered as potential early markers of obesity based on the reported associations. Possible early markers of obesity included maternal smoking and maternal weight gain during pregnancy. Probable early markers of obesity included maternal body mass index, childhood growth patterns (early rapid growth and early adiposity rebound), childhood obesity and father's employment (a proxy measure for SES in many studies). Health promotion programmes/agencies should consider these factors as reasonable targets to reduce the risk of adult obesity.

Prevalence and independent predictors of insulin resistance in children from Crete, Greece: the Children Study

BACKGROUND

It has been proposed that insulin resistance (IR) is associated with the development of Type 2 diabetes mellitus and cardiovascular disease. The aim of this study is to determine the prevalence of IR in Greek schoolchildren and to investigate factors associated with IR.

METHODS

Between October 2005 and March 2006, 522 children were recruited from Crete. Physical activity and dietary habits, anthropometric and biochemical characteristics, as well as medical history of pupils' parents were recorded. IR was estimated using the homeostasis model assessment (HOMA-IR), fasting glucose-to-insulin ratio (FGIR) and quantitative insulin sensitivity check index (QUICKI). Multiple linear regression was used to determine independent predictors for IR.

RESULTS

Fasting insulin levels and HOMA-IR scores were higher in obese children and girls compared with their normal-weight peers (P < 0.001). Moreover, the former had lower values in FGIR and QUICKI indices compared with the latter, indicating that obese children and girls are more insulin resistant compared with their counterparts (P < 0.001). The prevalence of IR was 9.2% (2.9% in normal-weight, 10.5% in overweight and 31.0% in obese children), using as a threshold HOMA-IR > 2.10 97.5th percentile of normal-weight participants). Multiple linear regression revealed that central adiposity, female gender and intake of simple carbohydrates is associated positively with HOMA-IR values, even after controlling for many other factors.

CONCLUSION

These findings demonstrate that girls and obese children, particularly those with central adiposity, are at high risk of developing IR. Therefore, these groups should be targets of Type 2 diabetes mellitus and cardiovascular disease preventive interventions.

Exploring the underlying hormonal mechanisms of prenatal risk factors for breast cancer: a review and commentary

Prenatal factors have been hypothesized to influence subsequent breast cancer development. Directly evaluating the associations of in utero exposures with risk, however, presents several methodologic and theoretical challenges, including the long induction period between exposure and disease and the lack of certainty regarding the critical timing of exposure. Indirect evaluation of these associations has been achieved by use of proxies such as gestational and neonatal characteristics. Evidence suggests that preeclampsia is associated with a reduced breast cancer risk, whereas high birth weight and dizygotic twinning seem associated with an increased risk. Asians born in Asia have substantially lower breast cancer risks than women born in the West. Although data thus far are few, what exists is not consistent with a unifying hypothesis for a particular biological exposure (such as estrogens or androgens) during pregnancy as mediating the observed associations between pregnancy factors and breast cancer risk. This suggests that additional studies of prenatal factors should seek to broaden the range of hormones, growth, and other endocrine factors that are evaluated in utero. Once candidate biomarkers are identified, assessing them with respect to breast cancer and with intermediate end points in carcinogenesis should be a priority. In addition, investigations should explore the possibility that in utero exposures may not act directly on the breast, but may alter other physiologic pathways such as hormone metabolism that have their effect on risk later in life.

Oxidative stress and antioxidant status in fetal circulation in preeclampsia

Preeclampsia is associated with oxidative stress in maternal circulation. The purpose of this study was to explore oxidative stress and antioxidants in the fetal circulation in preeclampsia. Women with preeclampsia (n = 19) or uncomplicated pregnancies (n = 33) delivered by cesarean section were included. Blood was sampled separately from the umbilical vein and artery. 8-Iso-prostaglandin F(2alpha) (8-isoprostane), a stable product of lipid peroxidation, is a reliable marker of oxidative stress. Concentration of total 8-isoprostane in cord plasma was analyzed by gas chromatography-mass spectrometry. Antioxidant status was evaluated measuring ferric reducing ability of plasma and vitamin E. There was no difference between preeclampsia and control groups regarding median plasma concentration of 8-isoprostane in umbilical vein (955 versus 780 pg/mL, p = 0.41) or in umbilical artery (233 versus 276 pg/mL, p = 0.65). Concentration of 8-isoprostane was much higher in plasma from the umbilical vein than artery, suggesting placenta as the source of 8-isoprostane. Median ferric reducing ability of plasma concentration was higher in preeclampsia than in controls, both in the umbilical vein and artery. Median vitamin E concentration in the umbilical vein was higher in preeclampsia, but no difference was found in the umbilical artery. In conclusion, no evidence of increased oxidative stress, evaluated by 8-isoprostane concentration, was found in fetal circulation in preeclampsia.

How the endothelium and its bone marrow-derived progenitors influence development of disease

The association between diseases accompanied by abnormal endothelial/vascular function (atherosclerosis, hypertension, diabetes mellitus, preeclampsia), and conditions characterized by increased tissue growth and normal endothelial/vascular function (cancer, placental size, birth length, adult height) could be caused by inherited characteristics of endothelial cells and their bone marrow-derived precursors. The genotype responsible for normal endothelial/precursor function could be modified by intrauterine and postnatal endothelial injury; telomere shortening caused by increased endothelial precursor proliferation in response to injury can result in premature endothelial senescence and a decreased precursor proliferative potential, thereby leading to an abnormal endothelial/precursor phenotype and the associated diseases. The individual endothelial/precursor phenotype could be established early in life and its changes in response to risk factors for diseases followed over time, thus providing a unique opportunity for identification and early institution of prophylactic and therapeutic interventions in diseases that cause most of the morbidity and mortality in advanced industrialized societies.

The influence of birthweight and intrauterine environment on adiposity and fat distribution in later life

OBJECTIVE

To review the literature on the association between birthweight and body mass index (BMI) and obesity in later life.

METHODS

Included in the review were papers appearing in Medline since 1966 and identified using the search terms obesity, body fat, waist, body constitution, birthweight and birth weight. Further papers were identified by examining bibliographies.

RESULTS

There is good evidence that there is an association between birthweight and subsequent BMI and overweight in young adults and children, which is linear and positive in some studies and J- or U-shaped in others. The evidence is less strong for middle-aged subjects. Studies that have assessed lean body mass (LBM) and fat body mass have tended to find that birthweight is positively associated with LBM and negatively associated with relative adiposity. This suggests that the association between birthweight and BMI/overweight does not necessarily reflect increased adiposity at higher birthweights. On controlling for current body mass there is fairly consistent evidence of a negative association between birthweight and a central pattern of fat distribution as measured by central:peripheral skinfold ratios. It has been suggested that the prenatal period is a 'critical' period for the development of adiposity, but it is unclear how far associations between birthweight and subsequent body habitus are genetic in origin and how far they result from intrauterine 'programming'. Two lines of evidence would suggest that the association is predominantly genetic. Studies of monozygotic twins have found environmentally determined differences in birthweight to be unrelated to subsequent BMI, and the association between birthweight and BMI is substantially reduced on controlling for parental BMI. However, some evidence of an influence of intrauterine environment on later obesity comes from studies of subjects who were exposed in utero to the effects of diabetes, famine conditions or smoking.

CONCLUSIONS

The reasons for the positive association between birthweight and BMI remain unclear. More studies including accurate measurement of body composition are needed to assess how far this relation is accounted for by changes in fat mass or by changes in lean mass. Studies with accurate measures of parental BMI would also be useful in assessing the importance of this confounder.

Exposures in childhood, adolescence and early adulthood and breast cancer risk: a systematic review of the literature

A growing body of work indicates that exposures over the life course have important roles to play in the aetiology of breast cancer. This review synthesises the literature that has been published in the area of early life events and female breast cancer risk. The review finds some evidence, primarily from cohort studies on the relationship between birthweight and breast cancer, to suggest that in utero events are related to breast cancer risk in adulthood. Strong evidence to support a positive association between height and breast cancer exists. Postulated mechanisms for this relationship include the role of early diet in subsequent disease risk, and the influence of endogenous growth factors mediating the relationship. There is some evidence to suggest that leg length is the component of height which is generating the observed associations between height and breast cancer. There is no consistent pattern of association between relative weight in childhood or adolescence and risk of breast cancer. The evidence to suggest an association between physical activity in early life and breast cancer risk is convincing from case-control studies, but is not fully substantiated by the results of three cohort studies. There are inconsistent results regarding the association between smoking at a young age and breast cancer risk. There is little evidence for an association between passive smoking in early life and breast cancer risk. No clear association between early drinking and breast cancer risk exists. These results are discussed in relation to possible underlying mechanisms and health promotion strategies which could reduce breast cancer risk.

Cancer risks in twins: results from the Swedish family-cancer database

Twin studies on cancer have addressed two general questions, one about the possible carcinogenic effects of twinning and the second about heritable effects of cancer. The first question is answered by comparing the occurrence of cancer in twins to that in singletons; the second is answered in probandwise analysis of monozygotic twins compared to dizygotic twins or siblings. We used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 62,574 0-66-year-old twins to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for all main cancer compared to cancer in singletons. In probandwise analysis, the SIR was calculated for the co-twin of an affected twin. The overall risk of cancer in same or opposite sex twins was at the level of the risk for singletons. Testicular cancer was increased among same sex twins and all twins to an SIR of 1.43. Melanoma was decreased in these groups of twins to an SIR of 0.84. Some other cancer sites were increased or decreased in some groups of twins, but none in all twins. The SIR of breast cancer was 1.01 and 1.04 in same and opposite sex twins, respectively. Probandwise analysis showed increased risks for Hodgkin's disease in males and breast cancer and childhood acute lymphoid leukemia among females. The data on this unselected population of twins suggest that twinning per se is not a risk factor of cancer. However, because twins are smaller than singletons at birth, some possible effects could be masked by such differences. In utero hormonal exposures may be related to the risk of testicular cancer. The protective effects in melanoma may be due to socioeconomic factors.