Birth weight and risk of type 2 diabetes in the black women's health study: does adult BMI play a mediating role?

Association between birth weight and insulin resistance in US adolescents: A retrospective cohort study exploring the role of concurrent body mass index

BACKGROUND AND AIMS

This study aimed to investigate the association between birth weight (BW) and abnormal HOMA-IR in US adolescents aged 12-15 years. The role of concurrent body mass index (BMI) in adolescence was also examined.

METHODS AND RESULTS

This retrospective cohort study included 3429 participants from NHANES with data in 1999-2020. HOMA-IR ≥2.3 was considered abnormal. Participants were classified as low (LBW; <2.5 kg), normal (NBW; 2.5-4.0 kg), or high (HBW; >4.0 kg) BW. Logistic regression was used to explore the association between BW and HOMA-IR. Mediation analysis was used to examine whether BMI z-score in adolescence mediated the association between BW and HOMA-IR. Compared with those in NBW, the odds ratios (95 % CI) of abnormal HOMA-IR in LBW and HBW groups were 1.26 (0.99-1.60), and 0.62 (0.47-0.83) respectively. The association between BW and abnormal HOMA-IR was consistent in all subgroups with no significant interactions. Mediation analysis showed that BW is associated with lower risk of HOMA-IR directly, but with higher risk indirectly via BMI in adolescence.

CONCLUSION

There was a negative linear relationship between BW and the prevalence of abnormal HOMA-IR in adolescents aged 12-15 independent of concurrent BMI. Children who were born with LBW but had high BMI in adolescence were of particularly higher risk of insulin resistance.

Association of Weight Trajectory With Severe Obesity: A Case-Control Study

Background: Early childhood weight trajectory is associated with future risk for obesity. However, little is known about the association of birth weight and weight trajectories before age 5.5 years with severe adult obesity. Methods: This study used a nested case-control design of 785 matched sets of cases and controls matched 1:1 on age and gender from a 1976 to 1982 birth cohort in Olmsted County, Minnesota. Cases with severe adult obesity were defined as individuals with a BMI ≥40 kg/m2 after 18 years of age. There were 737 matched sets of cases and controls for the trajectory analysis. Weight and height data from birth through 5.5 years were abstracted from the medical records, and weight-for-age percentiles were obtained from the CDC growth charts. Results: A two-cluster weight-for-age trajectory solution was identified as optimal, with cluster 1 having higher weight-for-age before age 5.5 years. While there was no association between birth weight and severe adult obesity, the odds of being in cluster 1, which includes children with higher weight-for-age percentiles, was significantly increased for cases compared with controls [odds ratio (OR) 1.99, 95% confidence interval (CI) 1.60-2.47]. The association between cluster membership and case-control status persisted after adjusting for maternal age and education (adjusted OR 2.08, 95% CI 1.66-2.61). Conclusions: Our data suggest that early childhood weight-for-age trajectories are associated with severe obesity status in adult life. Our results add to growing evidence that it is critical to prevent excess early childhood weight gain.

The early life course-related traits with three psychiatric disorders: A two-sample Mendelian randomization study

Objectives

Several studies have indicated a potential association between early life course-related traits and neurological and psychiatric disorders in adulthood, but the causal link remains unclear.

Methods

Instrumental variables (IVs) that have been shown to be strongly associated with exposure were obtained from summary data of genome-wide association studies (GWASs). Four early life course-related traits [i.e., birthweight (BW), childhood body mass index (BMI), early body size, and age at first birth (AFB)] were used as exposure IVs to estimate their causal associations with three neurological and psychiatric diseases [i.e., Alzheimer's disease (AD), major depressive disorder (MDD), and attention-deficit hyperactivity disorder (ADHD)]. Four different statistical methods, i.e., inverse-variance weighting (IVW), MR-Egger (MRE), weighted median (WM), and weighted mode (Wm), were performed in our MR analysis. Sensitivity analysis was performed by using the leave-one-out method, and horizontal pleiotropy was assessed using the MR-PRESSO package.

Results

There was evidence suggesting that BW has a causal effect on AD (OR_MR-PRESSO = 1.05, p = 1.14E-03), but this association was not confirmed via multivariable Mendelian randomization (MVMR) (OR_MVMR = 0.97, 95% CI 0.92-1.02, p = 3.00E-01). A strong relationship was observed between childhood BMI and ADHD among both sexes; a 1-SD increase in BMI significantly predicted a 1.46-fold increase in the OR for ADHD (p = 9.13E-06). In addition, a similar relationship was found between early life body size and ADHD (OR_MR-PRESSO = 1.47, p = 9.62E-05), and this effect was mainly driven by male participants (OR_MR-PRESSO = 1.50, p = 1.28E-3). Earlier AFB could significantly predict a higher risk of MDD (OR_MR-PRESSO = 1.19, p = 1.96E-10) and ADHD (OR_MR-PRESSO = 1.45, p = 1.47E-15). No significant causal associations were observed between the remaining exposures and outcomes.

Conclusion

Our results reveal the adverse effects of childhood obesity and preterm birth on the risk of ADHD later in life. The results of MVMR also show that lower BW may have no direct relationship with AD after adjusting for BMI. Furthermore, AFB may predict a higher risk of MDD.

Early onset of immune-mediated diseases in minority ethnic groups in the UK

BACKGROUND

The prevalence of some immune-mediated diseases (IMDs) shows distinct differences between populations of different ethnicities. The aim of this study was to determine if the age at diagnosis of common IMDs also differed between different ethnic groups in the UK, suggestive of distinct influences of ethnicity on disease pathogenesis.

METHODS

This was a population-based retrospective primary care study. Linear regression provided unadjusted and adjusted estimates of age at diagnosis for common IMDs within the following ethnic groups: White, South Asian, African-Caribbean and Mixed-race/Other. Potential disease risk confounders in the association between ethnicity and diagnosis age including sex, smoking, body mass index and social deprivation (Townsend quintiles) were adjusted for. The analysis was replicated using data from UK Biobank (UKB).

RESULTS

After adjusting for risk confounders, we observed that individuals from South Asian, African-Caribbean and Mixed-race/Other ethnicities were diagnosed with IMDs at a significantly younger age than their White counterparts for almost all IMDs. The difference in the diagnosis age (ranging from 2 to 30 years earlier) varied for each disease and by ethnicity. For example, rheumatoid arthritis was diagnosed at age 49, 48 and 47 years in individuals of African-Caribbean, South Asian and Mixed-race/Other ethnicities respectively, compared to 56 years in White ethnicities. The earlier diagnosis of most IMDs observed was validated in UKB although with a smaller effect size.

CONCLUSION

Individuals from non-White ethnic groups in the UK had an earlier age at diagnosis for several IMDs than White adults.

The Causal Evidence of Birth Weight and Female-Related Traits and Diseases: A Two-Sample Mendelian Randomization Analysis

Objectives: A large meta-analysis indicated a more pronounced association between lower birth weight (BW) and diseases in women but less concern about the causality between BW and female-related phenotypes and diseases.

Methods: Mendelian randomization (MR) analysis was used to estimate the causal relationship between two traits or diseases using summary datasets from genome-wide association studies. Exposure instrumental variables are variants that are strongly associated with traits and are tested using four different statistical methods, including the inverse variance weighting, MR-Egger, weighted median, and weighted mode in MR analysis. Next, sensitivity analysis and horizontal pleiotropy were assessed using leave-one-out and MR-PRESSO packages.

Results: The body mass index (BMI) in adulthood was determined by BW (corrected β = 0.071, p = 3.19E-03). Lower BW could decrease the adult sex hormone-binding globulin (SHBG) level (β = −0.081, p = 2.08E-06), but it resulted in increased levels of bioavailable testosterone (bio-T) (β = 0.105, p = 1.25E-05). A potential inverse effect was observed between BW and menarche (corrected β = −0.048, p = 4.75E-03), and no causal association was confirmed between BW and the risk of endometriosis, leiomyoma, and polycystic ovary syndrome.

Conclusion: Our results suggest that BW may play an important role and demonstrates a significant direct influence on female BMI, SHBG and bio-T levels, and menarche.

Admixture mapping of anthropometric traits in the Black Women's Health Study: evidence of a shared African ancestry component with birth weight and type 2 diabetes

Prevalence of obesity, type 2 diabetes (T2D), and being born with low birth weight are much higher in African American women compared to U.S. white women. Genetic factors may contribute to the excess risk of these conditions. We conducted admixture mapping of body mass index (BMI) at age 18, adult BMI, and adult waist circumference and waist-to-hip ratio adjusted for BMI using 2918 ancestral informative markers in 2596 participants of the Black Women's Health Study. We also searched for evidence of shared African genetic ancestry components among the four examined anthropometric traits and among birth weight and T2D. We found that global percent African ancestry was associated with higher adult BMI. We also found that African ancestry at 9q34 was associated with lower BMI at age 18. Our shared ancestry analysis identified ten genomic regions with local African ancestry associated with multiple traits. Seven out of these ten genomic loci were related to T2D risk. Of special interest is the 12q14-21 region where local African ancestry was associated with low birth weight, low BMI, high BMI-adjusted waist-to-hip ratio, and high T2D risk. Findings in the 12q14-21 genomic locus are consistent with the fetal insulin hypothesis that postulates that low birth weight and T2D have a common genetic basis, and they support the hypothesis of a shared African genetic ancestry component linking low birth weight and T2D in African Americans. Future studies should identify the actual genetic variants responsible for the clustering of these conditions in African Americans.

Association of diabetes-related variants in ADCY5 and CDKAL1 with neonatal insulin, C-peptide, and birth weight

BACKGROUND AND PURPOSE

Neonates at the highest and lowest percentiles of birth weight present an increased risk of developing metabolic diseases in adult life. While environmental events in utero may play an important role in this association, some genetic variants are associated both with birth weight and type 2 diabetes mellitus (T2DM), suggesting a genetic link between intrauterine growth and metabolism in adult life. Variants rs11708067 in ADCY5 and rs7754840 in CDKAL1 are associated with low birth weight, risk of T2DM, and lower insulin secretion in adults. We aimed to investigate whether, besides birth weight, these polymorphisms were related to insulin secretion at birth.

METHODS

A cohort of 218 healthy term newborns from uncomplicated pregnancies were evaluated for anthropometric and biochemical variables. Cord blood insulin and C-peptide were analyzed by ELISA. Genotyping of rs11708067 in ADCY5 and rs7754840 in CDKAL1 was performed.

RESULTS

Newborns carrying the A allele of ADCY5 rs11708067 had lower cord blood insulin and C-peptide, even after adjusting by maternal glycemia, HbA1c, and pregestational BMI. Lower birth weight was found for AA-AG genotypes compared to GG, but no differences were seen in adjusted birth weight or z-score. Variant rs7754840 in CDKAL1 was not associated with birth weight, neonatal insulin, or C-peptide for any genotype or genetic model.

CONCLUSIONS

The variant rs11708067 in ADCY5 is associated with lower neonatal insulin and C-peptide concentrations. Our results suggest that the genetic influence on insulin secretion may be evident from birth, even in healthy newborns, independently of maternal glycemia and BMI.

Genetic architecture of type 2 diabetes and its shared genetic component with low birth weight in African Americans

PURPOSE OF REVIEW

Recent large-scale multiancestry efforts has contributed to our knowledge of the hereditary basis of type 2 diabetes (T2D). The present review will summarize findings of the genetic basis of T2D in African Americans, a population group with a disproportionate burden of this disease.

RECENT FINDINGS

To date, >400 risk genetic variants have been found to be associated with the risk of T2D across populations of different ancestries. Although these findings are based on primarily European-ancestry populations, most of the identified loci show similar associations in African Americans. Ancestry-specific analyses including genome-wide associations studies (GWAS) in African Americans, Africans; as well as admixture mapping scans in African Americans have identified additional risk variants and genomic loci associate with the risk of T2D. These efforts have also uncovered new genetic links between low birth weight and T2D. In particular, admixture mapping approaches have identified a shared genetic ancestry component of both phenotypic traits in African Americans.

SUMMARY

Recent findings have helped us to better understand the genetic basis of T2D in African Americans. Of particular interest are new genetic discoveries linking low birth weight and T2D, two conditions with a much higher prevalence in African Americans compared to U.S. whites. Continuing work, including large-scale sequencing efforts would add to our knowledge of the genetic architecture of T2D in African Americans, as well as genetic links with other conditions.

Glycaemic control and outcomes in children with type 2 diabetes diagnosed at or before 10 years of age

Background

Type 2 diabetes (T2DM) in children is considered rare before puberty.

Objective

Describe the characteristics and outcomes of children with T2DM diagnosed at or before 10 years of age.

Methods

Retrospective electronic medical record review of children diagnosed with T2DM at a University Children's Hospital over 12 years was conducted. Patient characteristics at diagnosis, 2-3-year follow-up, and 4-5-year follow-up were analysed as a whole and by age groups, 5-8 and 9-10 years.

Results

There were 42 children ≤ 10 years with T2DM (5-8-year age group, n = 8 and 9-10-year age group, n = 34). There were 88.1% African American, 11.9% Caucasian, and 88.1% females. Body mass index (BMI) was ≥95th percentile in 95.2%. Average BMI z score was 2.5 ± 0.4 and higher in the 5-8-year age group (2.7 ± 0.5 vs 2.4 ± 0.4, P = .02). Average haemoglobin A1C at diagnosis was 10.5 ± 2.4%, and improvement was seen at 2-3 years, but subsequent worsening was noted at 4-5 years in both age groups. At 4-5 years after diagnosis, 93.9% required insulin for management of their hyperglycaemia, 21.2% had hypertension requiring treatment, 28.6% had low-density lipoprotein ≥130 mg/dL, and 28.6% had high-density lipoprotein <40 mg/dL.

Conclusions

T2DM at or below 10 years of age disproportionately affected females and ethnic minorities and was associated with morbid obesity. The majority of these children did not achieve glycaemic control and required insulin for management of their hyperglycaemia after 4-5 years, indicating the need for increased awareness of T2DM and intensive treatment in this special group.

Premature birth, low birth weight, small for gestational age and chronic non-communicable diseases in adult life: A systematic review with meta-analysis

BACKGROUND

Individuals who were born prematurely (PT), with low birth weight (LBW), or small for gestational age (SGA) appear to present a set of permanent changes that make them more susceptible to develop chronic non-communicable diseases (CNCD) in adult life.

AIM

Investigating the association between PT birth, LBW or SGA at birth and CNCD incidence in adult life.

METHODS

Systematic review with meta-analysis of studies available in three databases - two of them are official (PubMed and Web of Science) and one is gray literature (OpenGrey) - based on pre-established search and eligibility criteria.

RESULTS

Sixty-four studies were included in the review, 93.7% of them only investigated one of the exposure variables (46.7% LBW, 35.0% PT and 18.3% SGA at birth), whereas 6.3% investigated more than one exposure variable (50.0% LBW and PT; 50.0% SGA and PT). There was association among all exposure variables in the following outcomes: cardiometabolic (CMD) and glycidic metabolism (GMD) disorders, changes in body composition and risk of developing metabolic syndrome (MS). Female sex was identified as risk factor in the exposure-outcome association. Eighteen (18) articles were included in the meta-analysis. There was positive association between LBW and incidence of CMD (OR: 1.25 [95%CI: 1.11; 1.41]; 07 studies), GMD (OR: 1.70 [95%CI: 1.25; 2.30]; 03 studies) and MS (OR: 1.75 [95%CI: 1.27; 2.40]; 02 studies) in adult life. PT was positively associated with CMD (OR: 1.38 [95%CI: 1.27; 1.51]; 05 studies).

CONCLUSIONS

LBW and PT are associated with CMD and GMD development, as well as with the risk of developing MS in adult life.

Early Life Famine Exposure, Ideal Cardiovascular Health Metrics, and Risk of Incident Diabetes: Findings From the 4C Study

OBJECTIVE

We aim to investigate the impact of ideal cardiovascular health metrics (ICVHMs) on the association between famine exposure and adulthood diabetes risk.

RESEARCH DESIGN AND METHODS

This study included 77,925 participants from the China Cardiometabolic Disease and Cancer Cohort (4C) Study who were born around the time of the Chinese Great Famine and free of diabetes at baseline. They were divided into three famine exposure groups according to the birth year, including nonexposed (1963-1974), fetal exposed (1959-1962), and childhood exposed (1949-1958). Relative risk regression was used to examine the associations between famine exposure and ICVHMs on diabetes.

RESULTS

During a mean follow-up of 3.6 years, the cumulative incidence of diabetes was 4.2%, 6.0%, and 7.5% in nonexposed, fetal-exposed, and childhood-exposed participants, respectively. Compared with nonexposed participants, fetal-exposed but not childhood-exposed participants had increased risks of diabetes, with multivariable-adjusted risk ratios (RRs) (95% CIs) of 1.17 (1.05-1.31) and 1.12 (0.96-1.30), respectively. Increased diabetes risks were observed in fetal-exposed individuals with nonideal dietary habits, nonideal physical activity, BMI ≥24.0 kg/m², or blood pressure ≥120/80 mmHg, whereas significant interaction was detected only in BMI strata (P for interaction = 0.0018). Significant interactions have been detected between number of ICVHMs and famine exposure on the risk of diabetes (P for interaction = 0.0005). The increased risk was observed in fetal-exposed participants with one or fewer ICVHMs (RR 1.59 [95% CI 1.24-2.04]), but not in those with two or more ICVHMs.

CONCLUSIONS

The increased risk of diabetes associated with famine exposure appears to be modified by the presence of ICVHMs.

Birth Weight and Stroke in Adult Life: Genetic Correlation and Causal Inference With Genome-Wide Association Data Sets

Objective

Prior studies have shown that there is an inverse association between birth weight and stroke in adulthood; however, whether such association is causal remains yet known and those studies cannot distinguish between the direct fetal effect and the indirect maternal effect. The aim of the study is to untangle such relationship using novel statistical genetic approaches.

Methods

We first utilized linkage disequilibrium score regression (LDSC) and Genetic analysis incorporating Pleiotropy and Annotation (GPA) to estimate the overall genetic correlation between birth weight and stroke. Then, with a set of valid birth-weight instruments which had adjusted fetal and maternal effects, we performed a two-sample Mendelian randomization (MR) to evaluate its causal effect on stroke based summary statistics from large scale genome-wide association study (GWAS) (n = 264,498 for birth weight and 446,696 for stroke). We further validated the MR results with extensive sensitivity analyses.

Results

Both LDSC and GPA demonstrated significant evidence of shared maternal genetic foundation between birth weight and stroke, with the genetic correlation estimated to −0.176. However, no fetal genetic correlation between birth weight and stroke was detected. Furthermore, the inverse variance weighted MR demonstrated the maternally causal effect of birth weight on stroke was 1.12 (95% confidence interval [CI] 1.00–1.27). The maternal ORs of birth weight on three subtypes of stroke including cardioembolic stroke (CES), large artery stroke (LAS) and small vessel stroke (SVS) were 1.16 (95% CI 0.93–1.43), 1.50 (95% CI 1.14–1.96) and 1.47 (95% CI 1.15–1.87), respectively. In contrast, no fetal causal associations were found between birth weight and stroke or the subtypes. Those results were robust against extensive sensitivity analyses, with Egger regression ruling out the possibility of pleiotropy and multivariable MR excluding the likelihood of confounding or mediation effects of other risk factors of stroke.

Conclusion

This study provides empirically supportive evidence on the fetal developmental origins of stroke and its subtypes. However, further investigation is warranted to understand the pathophysiological role of low birth weight in developing stroke.

Development and Validation of a Risk Score to Predict Low Birthweight Using Characteristics of the Mother: Analysis from BUNMAP Cohort in Ethiopia

At least one ultrasound is recommended to predict fetal growth restriction and low birthweight earlier in pregnancy. However, in low-income countries, imaging equipment and trained manpower are scarce. Hence, we developed and validated a model and risk score to predict low birthweight using maternal characteristics during pregnancy, for use in resource limited settings. We developed the model using a prospective cohort of 379 pregnant women in South Ethiopia. A stepwise multivariable analysis was done to develop the prediction model. To improve the clinical utility, we developed a simplified risk score to classify pregnant women at high- or low-risk of low birthweight. The accuracy of the model was evaluated using the area under the receiver operating characteristic curve (AUC) and calibration plot. All accuracy measures were internally validated using the bootstrapping technique. We evaluated the clinical impact of the model using a decision curve analysis across various threshold probabilities. Age at pregnancy, underweight, anemia, height, gravidity, and presence of comorbidity remained in the final multivariable prediction model. The AUC of the model was 0.83 (95% confidence interval: 0.78 to 0.88). The decision curve analysis indicated the model provides a higher net benefit across ranges of threshold probabilities. In general, this study showed the possibility of predicting low birthweight using maternal characteristics during pregnancy. The model could help to identify pregnant women at higher risk of having a low birthweight baby. This feasible prediction model would offer an opportunity to reduce obstetric-related complications, thus improving the overall maternal and child healthcare in low- and middle-income countries.

Association between birth weight and diabetes: Role of body mass index and lifestyle in later life

BACKGROUND

This study investigated the association between birth weight and diabetes in a Chinese population, and the effects of body mass index (BMI) and lifestyle factors in later life on this association.

METHODS

Data from 49 118 participants aged ≥40 years with recalled birth weight from the Risk Evaluation of cAncers in Chinese diabeTic Individuals: a lONgitudinal (REACTION) study, a nationwide population-based cohort, were used. Diabetes diagnosis was based on oral glucose tolerance tests and HbA1c measurements. Logistic regression models were used to evaluate the association of birth weight and risk of diabetes in later life.

RESULTS

Increased risk of diabetes was associated with lower or higher birth weight. Compared with individuals with a birth weight of 2500 to 3499 g, the odds ratios (ORs) and 95% confidence intervals (CIs) of diabetes for individuals with a birth weight of <2500, between 3500 and 3999, and ≥4000 g were 1.28 (1.11-1.47), 1.11 (1.04-1.19), and 1.20 (1.07-1.34), respectively. Significant associations were prominent in participants with a current BMI ≥24 kg/m² , but not detected in those with a normal BMI (OR 1.20 [95% CI 0.96-1.49], 1.11 [95% CI 0.98-1.25], and 1.10 [95% CI 0.89-1.37], respectively). Moreover, there was no increased risk of diabetes in individuals with a low birth weight but with healthy dietary habits (OR 0.94; 95% CI 0.68-1.29) or ideal physical activity (OR 1.41; 95% CI 0.97-2.04).

CONCLUSIONS

A U-shaped association was observed between birth weight and the risk of diabetes. Healthy lifestyles (healthy dietary habits or ideal physical activity) may eliminate the negative effects of low birth weight in the development of diabetes, but not the effect of high birth weight.

Association of Birth Weight With Type 2 Diabetes and Glycemic Traits: A Mendelian Randomization Study

IMPORTANCE

Observational studies have shown associations of birth weight with type 2 diabetes (T2D) and glycemic traits, but it remains unclear whether these associations represent causal associations.

OBJECTIVE

To test the association of birth weight with T2D and glycemic traits using a mendelian randomization analysis.

DESIGN, SETTING, AND PARTICIPANTS

This mendelian randomization study used a genetic risk score for birth weight that was constructed with 7 genome-wide significant single-nucleotide polymorphisms. The associations of this score with birth weight and T2D were tested in a mendelian randomization analysis using study-level data. The association of birth weight with T2D was tested using both study-level data (7 single-nucleotide polymorphisms were used as an instrumental variable) and summary-level data from the consortia (43 single-nucleotide polymorphisms were used as an instrumental variable). Data from 180 056 participants from 49 studies were included.

MAIN OUTCOMES AND MEASURES

Type 2 diabetes and glycemic traits.

RESULTS

This mendelian randomization analysis included 49 studies with 41 155 patients with T2D and 80 008 control participants from study-level data and 34 840 patients with T2D and 114 981 control participants from summary-level data. Study-level data showed that a 1-SD decrease in birth weight due to the genetic risk score was associated with higher risk of T2D among all participants (odds ratio [OR], 2.10; 95% CI, 1.69-2.61; P = 4.03 × 10-5), among European participants (OR, 1.96; 95% CI, 1.42-2.71; P = .04), and among East Asian participants (OR, 1.39; 95% CI, 1.18-1.62; P = .04). Similar results were observed from summary-level analyses. In addition, each 1-SD lower birth weight was associated with 0.189 SD higher fasting glucose concentration (β = 0.189; SE = 0.060; P = .002), but not with fasting insulin, 2-hour glucose, or hemoglobin A1c concentration.

CONCLUSIONS AND RELEVANCE

In this study, a genetic predisposition to lower birth weight was associated with increased risk of T2D and higher fasting glucose concentration, suggesting genetic effects on retarded fetal growth and increased diabetes risk that either are independent of each other or operate through alterations of integrated biological mechanisms.

Causal Association Between Birth Weight and Adult Diseases: Evidence From a Mendelian Randomization Analysis

Purpose: Birth weight has a profound long-term impact on individual’s predisposition to various diseases at adulthood—a hypothesis commonly referred to as the fetal origins of adult diseases. However, it is not fully clear to what extent the fetal origins of adult diseases hypothesis holds and it is also not completely known what types of adult diseases are causally affected by birth weight.

Materials and methods: Mendelian randomization using multiple genetic instruments associated with birth weight was performed to explore the causal relationship between birth weight and adult diseases. The causal relationship between birth weight and 21 adult diseases as well as 38 other complex traits was examined based on data collected from 37 large-scale genome-wide association studies with up to 340,000 individuals of European ancestry. Causal effects of birth weight were estimated using inverse-variance weighted methods. The identified causal relationships between birth weight and adult diseases were further validated through extensive sensitivity analyses, bias calculation, and simulations.

Results: Among the 21 adult diseases, three were identified to be inversely causally affected by birth weight after the Bonferroni correction. The measurement unit of birth weight was defined as its standard deviation (i.e., 488 g), and one unit lower birth weight was causally related to an increased risk of coronary artery disease (CAD), myocardial infarction (MI), type 2 diabetes (T2D), and BMI-adjusted T2D, with the estimated odds ratios of 1.34 [95% confidence interval (CI) 1.17–1.53], 1.30 (95% CI 1.13–1.51), 1.41 (95% CI 1.15–1.73), and 1.54 (95% CI 1.25–1.89), respectively. All these identified causal associations were robust across various sensitivity analyses that guard against various confounding due to pleiotropy or maternal effects as well as reverse causation. In addition, analysis on 38 additional complex traits did not identify candidate traits that may mediate the causal association between birth weight and CAD/MI/T2D.

Conclusions: The results suggest that lower birth weight is causally associated with an increased risk of CAD, MI, and T2D in later life, supporting the fetal origins of adult diseases hypothesis.

Birth weight and risk of type 2 diabetes: A dose-response meta-analysis of cohort studies

The association between birth weight and type 2 diabetes mellitus has been debated for several decades. The objective of this systematic review and meta-analysis was to quantitatively clarify the association between birth weight and risk of type 2 diabetes mellitus based on cohort studies. We searched PubMed, Web of Science, and Embase databases for cohort study articles on the association between birth weight and risk of type 2 diabetes mellitus published up to 1 March 2018. Random effects of generalized least square regression models were used to estimate relative risk (RR). Restricted cubic splines were conducted to model the dose-response relationship. We included 21 studies (19 articles) involving 1 041 879 individuals and 35 699 cases of type 2 diabetes mellitus, with follow-up ranged from 6 to 47 years. We identified significant decreasing trend for the highest versus lowest category of birth weight for the association with type 2 diabetes mellitus risk: The risk was reduced by 35% (RR, 0.65; 95% confidence interval [CI], 0.53-0.81) and by 12% (RR 0.88; 95% CI, 0.85-0.91) per 500-g increment in birth weight. Our results showed a dose-response relationship between birth weight and diabetes risk, which was nonlinear (P_nonlinearity  < 0.001) and L-shaped. With increasing birth weight (<5000 g), the risk of type 2 diabetes mellitus decreased substantially. The association between birth weight and type 2 diabetes mellitus was curvilinear and L-shaped.

Adipose Tissue Mediates Associations of Birth Weight with Glucose Metabolism Disorders in Children

OBJECTIVE

This study aimed to examine the associations between low birth weight (LBW) versus high birth weight (HBW) and dysglycemia, including insulin resistance (IR) and impaired fasting glucose (IFG) in children, and aimed to explore the role of adipose tissue in these relationships.

METHODS

A total of 2,935 subjects aged 6 to 18 years were recruited to examine the relationship between birth weight and IR (defined as homeostasis model assessment of IR > 2.3) and IFG. Mediation analyses were conducted to examine the roles of various adipokines and anthropometrics in these relationships.

RESULTS

Children with LBW had a nearly twofold increased risk of IR and IFG compared with children with normal birth weight, even after adjusting for BMI. Decreased circulating adiponectin levels contributed to 21.2% of the LBW-IR relationship, whereas none of the selected adipose markers mediated the LBW-IFG relationship. In contrast, after controlling for current BMI or waist circumference, HBW reduced the risk of IR by 34%, but it was not associated with IFG. The HBW-IR relationship was significantly mediated by reduced leptin levels (21.4%) and fat mass percentage (8.8%), after controlling for BMI.

CONCLUSIONS

These findings suggest the potential role of adipose tissue dysfunction as an underlying mechanism for the birth weight-type 2 diabetes relationship.

Associations between birth weight and glucose intolerance in adulthood among Greenlandic Inuit

AIMS

To examine the association between birth weight and glucose intolerance in adult Greenlandic Inuit.

METHODS

We examined 1429 participants aged 18-56 years from two population-based, cross-sectional studies in Greenland with information on birth weight. Oral glucose tolerance tests, anthropometric measures and ultrasound of abdominal tissue were performed. Associations of birth weight with glucose markers were analysed using linear or logistic regressions. Spline analyses were conducted to examine u-shaped associations. Adjustments were done for age, sex, birth place, family history of diabetes, genetic admixture, TBC1D4 p.Arg684Ter carrier status, BMI and visceral adipose tissue.

RESULTS

The median birthweight was 3300 g and 3.9% had type 2 diabetes, T2DM. Spline analyses indicated overall linear associations. In fully adjusted analyses, an increase in birth weight of 1 kg was associated with a change in fasting plasma glucose of -0.06 mmol/L (95%CI: -0.11, -0.01), 2-h plasma glucose of -0.16 mmol/L (95%CI: -0.35, 0.02), HOMA-IR of -5.45% (95%CI: -10.34, -0.29), insulin sensitivity index of 7.04% (95%CI: 1.88, 12.45) and a trend towards a reduced risk of hyperglycaemia and T2DM, although statistically insignificant.

CONCLUSIONS

Birth weight was inversely associated with hepatic and peripheral insulin resistance independently of adult adiposity. Thus, the findings support low birth weight as a contributing factor for glucose intolerance in adult Inuit in Greenland.

Pre- and perinatal factors and incidence of breast cancer in the Black Women's Health Study

PURPOSE

The purpose of the study was to investigate the association between pre- or perinatal factors and breast cancer risk among African American women.

METHODS

Participants in the Black Women's Health Study, a prospective cohort of 59,000 African American women, reported birth weight, preterm birth, twin or triplet status, maternal age at birth, birth order, and having been breastfed during infancy at various times during follow-up from 1997 to 2015. Numbers of incident cases ranged from 312 for breastfed analyses to 1,583 for twin or triplet analyses. Using multivariable Cox proportional hazards regression, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between each factor and breast cancer risk overall and by estrogen receptor (ER) status.

RESULTS

Compared to birth weights of 5 lbs. 8 oz.-8 lbs. 13 oz., low (< 5 lbs. 8 oz.) and high (> 8 lbs. 13 oz.) birth weights were associated with increased breast cancer risk; HRs (95% CI) were 1.19 (0.98-1.44) and 1.26 (0.97-1.63), respectively. Associations were similar by ER status. Having been born to a mother aged ≥ 35 years versus < 20 years was associated with risk of ER+ (HR 1.59, 95% CI 1.10-2.29), but not ER- breast cancer. Other perinatal factors were not associated with breast cancer.

CONCLUSION

African American women with a low or high birth weight or born to older mothers may have increased breast cancer risk. Trends towards delayed child birth and higher birth weights, coupled with disproportionately high rates of low birth weight among African Americans, may contribute to increases in breast cancer incidence.

The association between birth weight and the risk of type 2 diabetes mellitus: a systematic review and meta-analysis

Previous studies have shown a relationship between type 2 diabetes mellitus and birth weight. We performed this meta-analysis to resolve the problem of inconsistent results. We conducted a literature search of PubMed, Embase and the Cochrane Library using "Diabetes Mellitus, Type 2," "Birth Weight," and some related free words. Twenty-one studies were included in accordance with inclusion and exclusion criteria, involving a total of 313,165 participants and 22,341 type 2 diabetes mellitus cases. A modified version of the Newcastle-Ottawa Scale was used to evaluate the methodological quality of studies included. We used Review Manager 5.3 for data merging and statistical analysis. Results were expressed as odds ratio (OR) and 95% confidence interval (95% CI). The risk of diabetes with low birth weight (<2,500 g) was higher than that with birth weight ≥2,500 g, (OR = 1.51, 95% CI: 1.43, 1.58). Compared with normal birth weight (2,500-4,000 g), low birth weight, but not high birth weight, increased the risk of diabetes (OR = 1.41, 95% CI: 1.26, 1.58). There is a negative association between birth weight and the future risk of type 2 diabetes mellitus.

Admixture mapping and fine-mapping of birth weight loci in the Black Women's Health Study

Several genome-wide association studies (GWAS) have identified genetic variants associated with birth weight. To date, however, most GWAS of birth weight have focused primarily on European ancestry samples even though prevalence of low birth weight is higher among African-Americans. We conducted admixture mapping using 2918 ancestral informative markers in 2596 participants of the Black Women's Health Study, with the goal of identifying novel genomic regions where local African ancestry is associated with birth weight. In addition, we performed a replication analysis of 11 previously identified index single nucleotide polymorphisms (SNPs), and fine-mapped those genetic loci to identify better or new genetic variants associated with birth weight in African-Americans. We found that high African ancestry at 12q14 was associated with low birth weight, and we identified multiple independent birth weight-lowering variants in this genomic region. We replicated the association of a previous GWAS SNP in ADRB1 and our fine-mapping efforts suggested the presence of new birth weight-associated variants in ADRB1, HMGA2, and SLC2A4. Further studies are needed to determine whether birth weight-associated loci can in part explain race-associated birth weight disparities.

Birthweight, Type 2 Diabetes Mellitus, and Cardiovascular Disease: Addressing the Barker Hypothesis With Mendelian Randomization

BACKGROUND

Low birthweight has been associated with a higher risk of hypertension, type 2 diabetes mellitus (T2D), and cardiovascular disease. The Barker hypothesis posits that intrauterine growth restriction resulting in lower birthweight is causal for these diseases, but causality is difficult to infer from observational studies.

METHODS

We performed regression analyses to assess associations of birthweight with cardiovascular disease and T2D in 237 631 individuals from the UK Biobank. Further, we assessed the causal relationship of such associations using Mendelian randomization.

RESULTS

In the observational analyses, birthweight showed inverse associations with systolic and diastolic blood pressure (β, -0.83 and -0.26; per raw unit in outcomes and SD change in birthweight; 95% confidence interval [CI], -0.90 to -0.75 and -0.31 to -0.22, respectively), T2D (odds ratio, 0.83; 95% CI, 0.79-0.87), lipid-lowering treatment (odds ratio, 0.84; 95% CI, 0.81-0.86), and coronary artery disease (hazard ratio, 0.85; 95% CI, 0.78-0.94), whereas the associations with adult body mass index and body fat (β, 0.04 and 0.02; per SD change in outcomes and birthweight; 95% CI, 0.03-0.04 and 0.01-0.02, respectively) were positive. The Mendelian randomization analyses indicated inverse causal associations of birthweight with low-density lipoprotein cholesterol, 2-hour glucose, coronary artery disease, and T2D and positive causal association with body mass index but no associations with blood pressure.

CONCLUSIONS

Our study indicates that lower birthweight, used as a proxy for intrauterine growth retardation, is causally related with increased susceptibility to coronary artery disease and T2D. This causal relationship is not mediated by adult obesity or hypertension.

Prenatal Development and Adolescent Obesity: Two Distinct Pathways to Diabetes in Adulthood

OBJECTIVE

Higher body-mass index (BMI) and lower birth weight (BW) are associated with elevated risk of diabetes in adulthood, but the extent to which they compose two distinct pathways is unclear.

METHODS

We used data from the National Longitudinal Study of Adolescent to Adult Health, a cohort of adolescents (1994-1995) followed for 14 years over four waves into adulthood (n = 13,413). Sex-stratified path analysis was used to examine pathways from BW [kg; linear (BW) and quadratic (BW2)] to latent trajectories in BMI from adolescence to adulthood to prevalent diabetes or prediabetes (pre/diabetes) in adulthood, adjusting for sociodemographic characteristics.

RESULTS

Two pathways from BW to pre/diabetes were characterized: one from higher BW to elevated BMI and pre/diabetes and a second from lower BW, independent of BMI. In the BMI-independent pathway, greater BW was associated with marginally lower odds of pre/diabetes in women, but not men. Girls born at lower and higher BW exhibited elevated BMI in adolescence [coeff (95% CI): BW: -2.1 (-4.1, -0.05); BW2: 0.43 (0.09, 0.76)]; higher BW predicted marginally faster BMI gain and higher adolescent BMI and faster BMI gain were associated with pre/diabetes [coeff (95% CI): BMI intercept: 0.09 (0.06, 0.11); BMI slope: 0.11 (0.07, 0.15)]. In boys, BW was weakly associated with BMI intercept and slope; BMI slope, but not BMI intercept, was positively associated with pre/diabetes [coeff (95% CI): 0.29 (0.19, 0.39)].

CONCLUSIONS

Findings suggest that in girls, slowing BMI gain is critical for diabetes prevention, yet it may not address distinct pathology stemming from early life.

Low Birth Weight, Cumulative Obesity Dose, and the Risk of Incident Type 2 Diabetes

BACKGROUND

Obesity history may provide a better understanding of the contribution of obesity to T2DM risk.

METHODS

17,634 participants from the 1958 National Child Development Study were followed from birth to 50 years. Cumulative obesity dose, a measure of obesity history, was calculated by subtracting the upper cut-off of the normal BMI from the actual BMI at each follow-up and summing the areas under the obesity dose curve. Hazard ratios (HRs) for diabetes were calculated using Cox regression analysis. Three separate models compared the predictive ability of cumulative obesity dose on diabetes risk with the time-varying BMI and last BMI.

RESULTS

In final models, 341 of 15,043 (2.27%) participants developed diabetes; male sex and low birth weight were significant confounding variables. Adjusted HRs were 1.080 (95% CI: 1.071, 1.088) per 10-unit cumulative obesity dose, 1.098 (95% CI: 1.080, 1.117) per unit of the time-varying BMI, and 1.146 (95% CI: 1.084, 1.212) per unit of the last BMI. Cumulative obesity dose provided the best predictive ability for diabetes.

CONCLUSIONS

Cumulative obesity dose is an improved method for evaluating the impact of obesity history on diabetes risk. The link between low birth weight and T2DM is strengthened by adjusting for cumulative obesity dose.

Birthweight and cardiometabolic risk patterns in multiracial children

BACKGROUND/OBJECTIVES

Prenatal growth, which is widely marked by birthweight, may have a pivotal role in affecting the lifelong risk of cardiometabolic disorders; however, comprehensive evaluation of its relations with childhood cardiometabolic risk patterns and the ethnic and gender disparities in national representative populations is still lacking. The aim of this study was to evaluate the associations between birthweight and comprehensive patterns of cardiometabolic risk in a nationally representative sample of children and adolescents.

SUBJECTS/METHODS

Prospective analyses were performed using data from 28 153 children 0 to 15 years in the National Health and Nutrition Examination Survey from 1999 through 2014. We defined childhood cardiometabolic disorders using standard definitions for obesity, high blood pressure, hyperglycemia and dyslipidemia.

RESULTS

Five birthweight categories <2.5, 2.5-3.0, 3.0-3.5, 3.5-4.2 and ⩾4.2 kg accounted for 8.2%, 17.9%, 35.7%, 27.9% and 10.4% of the population, respectively. In all children, with increasing birthweight, we observed significantly increasing trends of the risk of general and central obesity (P for trend <0.01) and significantly decreasing trends of the risk of high systolic blood pressure (SBP), high HbA1c and low high-density lipoprotein cholesterol (HDL-C) (P for trend <0.05). The associations were independent of current body mass index (BMI). In addition, we found that the relations of birthweight with high waist circumference in Black children showed U-shape, as well as high SBP in Mexican and Hispanic children. Moreover, we found that the associations of low birthweight with high SBP and low HDL-C appeared to more prominent significant in boys, whereas the inverse association with high HbA1c was more evident in girls.

CONCLUSIONS

Our data indicate that birthweight is significantly related to childhood cardiometabolic risk, independent of current BMI, and the associations exhibit race and gender-specific patterns.

The Association of Birth Weight and Infant Growth with Energy Balance-Related Behavior - A Systematic Review and Best-Evidence Synthesis of Human Studies

BACKGROUND

Suboptimal prenatal and early postnatal growths are associated with obesity in later life, but the underlying mechanisms are unknown. The aim of this study was to systematically review the literature that reports on the longitudinal association of (i) birth size or (ii) infant growth with later (i) energy intake, (ii) eating behaviors, (iii) physical activity or (iv) sedentary behavior in humans.

METHODS

A comprehensive search of MEDLINE, EMBASE, PsycINFO and The Cochrane Library was conducted to identify relevant publications. We appraised the methodological quality of the studies and synthesized the extracted data through a best-evidence synthesis.

RESULTS

Data from 41 publications were included. The quality of the studies was high in three papers, moderate in 11 and low in the large majority (n = 27) of papers appraised. Our best-evidence synthesis indicates that there is no evidence for an association of birth weight with later energy intake, eating behavior, physical activity or sedentary behavior. We found moderate evidence for an association of extreme birth weights (at both ends of the spectrum) with lower physical activity levels at a later age. Evidence for the association of infant growth with energy balance-related behavior was generally insufficient.

CONCLUSIONS

We conclude that current evidence does not support an association of early-life growth with energy balance-related behaviors in later life, except for an association of extreme birth weights with later physical activity.

Maternal C-reactive protein concentrations during pregnancy and birth weight in a prospective cohort in Rio de Janeiro, Brazil

OBJECTIVE

To evaluate the association between maternal C-reactive protein (CRP) concentrations during pregnancy and birth weight (BW) Z-score.

METHODS

A prospective cohort of pregnant women were followed at 5-13 (n = 203), 20-26 (n = 181), and 30-36 (n = 181) gestational weeks and at 30-45 d postpartum. Maternal CRP concentrations were assessed three times during pregnancy using immunoturbidimetric methods (ultra-sensitive kits). BW Z-score and newborns classified as small for gestational age (SGA) were evaluated according to Intergrowth-21st curves. Statistical analyses included SGA rates, BW Z-score means (SD) and a two-stage procedure: (1) a linear mixed-effect model (LME) to predict CRP intercept (mean exposure level) and slope (trend of change during pregnancy); and (2) a multiple linear regression model with BW Z-score as the outcome and CRP intercept and slope exposures.

RESULTS

A total of 4.4% (n = 9) women delivered SGA newborns. The mean BW was 3282.0 (37.3) g, and the mean gestational age at delivery was 38.8 (0.1) weeks. Women in the third tertile of the CRP rate of change gave birth to infants with a mean BW Z-score that was lower than those in the first/second tertiles (0.226 versus 0.381; p = 0.324). For the adjusted baseline CRP (β = 0.08; 95% CI: 0.03-0.14), the CRP trend of change was inversely associated with the BW Z-score (β= -3.77; 95% CI: -5.45 to -2.10).

CONCLUSIONS

The maternal CRP trend of change during pregnancy was negatively associated with BW Z-score.

Low birthweight and risk of type 2 diabetes: a Mendelian randomisation study

AIMS/HYPOTHESIS

Low birthweight has been associated with a high risk of type 2 diabetes mellitus in observational studies. However, it remains unclear whether this relation is causal.

METHODS

The present study included 3627 individuals with type 2 diabetes and 12,974 control participants of European ancestry from the Nurses' Health Study and the Health Professionals Follow-Up Study. A genetic risk score (GRS) was calculated based on five low-birthweight-related single nucleotide polymorphisms (SNPs). We assessed the evidence for causality first by examining the association of the GRS and the individual SNPs with type 2 diabetes, and second by performing a Mendelian randomisation analysis to estimate the potentially causal effect size of low birthweight on type 2 diabetes.

RESULTS

In a meta-analysis of the two studies, each 1 point increment in the GRS was associated with a 6% (95% CI 3%, 9%) higher risk of type 2 diabetes. CCNL1 rs900400 and 5q11.2 rs4432842 showed dose-response associations with risk of type 2 diabetes; the corresponding ORs and 95% CIs were 1.09 (1.03, 1.16) and 1.09 (1.02, 1.16), respectively. Furthermore, we observed an overall Mendelian randomisation OR of 2.94 (95% CI 1.70, 5.16; p < 0.001) for type 2 diabetes per 1 SD lower genetically determined birthweight.

CONCLUSIONS/INTERPRETATION

A genetically lowered birthweight was associated with increased susceptibility to type 2 diabetes. Our findings support a potential causal relation between birthweight and risk of type 2 diabetes, providing new evidence to support the role of intrauterine exposures in the pathogenesis of type 2 diabetes.

Birth weight was longitudinally associated with cardiometabolic risk markers in mid-adulthood

PURPOSE

Birth weight (BW) is associated with risk of cardiovascular (CV) disease. The findings from studies examined the association of BW with metabolic markers of CV risk were inconsistent and controversial. We examined the association of BW with insulin resistance and blood lipids using repeated measures up to mid-adulthood.

METHODS

Data from seven screenings of the Bogalusa Heart Study-a longitudinal study of cardiovascular risk factors in Bogalusa, LA-are analyzed using generalized estimation equations method. Participants with birth data and at least one measurement of study outcomes between 18 and 44 years (n = 2,034) were included.

RESULTS

BW is inversely associated with insulin resistance, triglycerides, and total cholesterol (P < .01 for all). For 1-kg decrease in BW, insulin resistance increased by 2.3 units, 95% confidence interval (CI) = 0.7-3.9; triglycerides by 8.7 mg per dL, 95% CI = 4.9-12.4, and total cholesterol by 5.4 mg per dL, 95% CI = 1.8-9.1. The association of body mass with adult blood lipids levels is weaker in persons with low versus normal BW.

CONCLUSIONS

The study provides strong evidence of an inverse relationship of BW with adulthood cardiometabolic risk profile. Persons born with low BW are maybe less responsive to preventive interventions aiming at weight reduction.

Low birth weight leads to obesity, diabetes and increased leptin levels in adults: the CoLaus study

BACKGROUND

Low birth weight is associated with increased rates of obesity, insulin resistance and type 2 diabetes, but the precise mechanisms for this association remain unclear. We aimed to assess the relationships between birth weight and markers of glucose homeostasis or obesity in adults.

METHODS

Cross-sectional population-based study on 1458 women and 1088 men aged 35-75 years living in Lausanne, Switzerland. Birth weight was self-reported and categorized into ≤ 2.5, 2.6-3.5, 3.6-4.0 and >4.0 kg. Body composition was assessed by bioimpedance. Leptin and adiponectin levels were measured by ELISA.

RESULTS

Women with low birth weight (≤ 2.5 kg) had higher levels of fasting plasma glucose, insulin, HOMA, diabetes and metabolic syndrome; a non significant similar trend was seen in men. In both genders, height increased with birth weight, whereas a U-shaped association was found between birth weight and body mass index, waist circumference and body fat percentage. After adjusting for age, smoking status, physical activity and fat mass, an inverse association was found between leptin and birth weight categories: adjusted mean ± standard error 17.3 ± 0.7, 16.2 ± 0.3, 15.6 ± 0.5 and 14.0 ± 0.8 ng/dL for birth weight categories ≤ 2.5, 2.6-3.5, 3.6-4.0 and >4.0 kg, respectively, in women (p < 0.05) and 9.8 ± 0.8, 9.1 ± 03, 7.8 ± 0.4 and 7.7 ± 0.5 ng/dL in men (p < 0.05). An inverse association was also found between reported birth weight and leptin to fat mass ratio: mean ± standard error 0.77 ± 0.04, 0.73 ± 0.02, 0.69 ± 0.03 and 0.62 ± 0.04 in women (p < 0.05); 0.46 ± 0.05, 0.45 ± 0.02, 0.39 ± 0.02 and 0.38 ± 0.03 in men (p < 0.05). No differences in adiponectin levels were found between birth weight groups.

CONCLUSIONS

Middle-aged adults born with a low weight present a higher prevalence of diabetes and obesity and also higher leptin levels and leptin to fat mass ratio than adults born with a normal weight. The higher leptin levels and leptin to fat mass ratio among adults born with a low weight might be related to nutritional factors during childhood or to the development of leptin resistance and/or higher leptin production by body fat unit. Subjects born with a low weight should be counselled regarding the risks of developing diabetes and/or cardiovascular disease.

Birth weight modifies the association between central nervous system gene variation and adult body mass index

Genome wide association studies have identified ~100 loci associated with body mass index (BMI). Persons with low birth weight have an increased risk of metabolic disorders. We postulate that normal mechanisms of body weight regulation are disrupted in subjects with low birth weight. The present analyses included 2215 African American women from the Black Women's Health Study, and were based on genotype data on 20 BMI-associated loci and self-reported data on birth weight, weight at age 18 and adult weight. We used general linear models to assess the association of individual single-nucleotide polymorphisms (SNPs) with BMI at age 18 and later in adulthood within strata of birth weight (above and below the median, 3200 g). Three SNPs (rs1320330 near TMEM18, rs261967 near PCSK1 and rs17817964 in FTO), and a genetic score combining these three variants, showed significant interactions with birth weight in relation to BMI. Among women with birth weight <3200 g, there was an inverse association between genetic score and BMI; beta-coefficient=-0.045 (95% confidence intervals (CI) -0.104, 0.013) for BMI at age 18, and -0.055 (95% CI -0.112, 0.002) for adult BMI. Among women with birth weight ⩾3200 g, genetic score was positively associated with BMI: beta-coefficient=0.110 (95% CI 0.051, 0.169) for BMI at age 18 (P for interaction=0.0002), and 0.112 (95% CI 0.054, 0.170) for adult BMI (P for interaction<0.0001). Because TMEM18, PCSK1 and FTO are highly expressed in the central nervous system (CNS), our results suggest that low-birth weight may disrupt mechanisms of CNS body weight regulation.

Novel Risk Factors for Type 2 Diabetes in African-Americans

In the USA, compared to whites, African-Americans are disproportionately impacted by the diabetes epidemic. Traditional diabetes risk factors, such as obesity, are more common among African-Americans, but these traditional risk factors do not explain all of the disparity in diabetes risk. Recent research has identified novel environmental, lifestyle, physiologic, and genetic risk factors for diabetes, some of which appear to impact African-Americans more than whites. This manuscript reviews the recent literature to highlight some of these novel risk factors that may be contributing to the racial disparity in diabetes risk. Further study is needed of the modifiable risk factors for development of interventions to reduce the risk of diabetes in African-Americans, as well as other high-risk populations.

Intergenerational transmission of the healthy immigrant effect (HIE) through birth weight: A systematic review and meta-analysis

This review examines intergenerational differences in birth weight among children born to first-generation and second-generation immigrant mothers and the extent to which they vary by country of origin and receiving country. We searched MEDLINE, EMBASE, Web of Science, PubMed, and ProQuest from inception to October 2014 for articles that recorded the mean birth weight (in grams) or odds of low birth weight (LBW) of children born to immigrant mothers and one subsequent generation. Studies were analyzed descriptively and meta-analyzed using Review Manager 5.3 software. We identified 10 studies (8 retrospective cohort and 2 cross-sectional studies) including 158,843 first and second-generation immigrant women. The United States and the United Kingdom represented the receiving countries with the majority of immigrants originating from Mexico and South Asia. Six studies were meta-analyzed for mean birth weight and seven for low birth weight. Across all studies, there was found to be no statistically significant difference in mean birth weight between first and second-generation children. However, the odds of being LBW were 1.21 [95% CI, 1.15, 1.27] times greater among second-generation children. Second-generation children of Mexican descent in particular were at increased odds of LBW (OR = 1.47 [95% CI, 1.28, 1.69]). In the United States, second-generation children were at 34% higher odds of being LBW (OR = 1.34 [95% CI, 1.13, 1.58]) when compared to their first-generation counterparts. This effect was slightly smaller in the United Kingdom (OR = 1.18 [95% CI, 1.13, 1.23]). In conclusion, immigration to a new country may differentially influence low birth weight over generations, depending on the mother's nativity and the country she immigrates to.

The need for dialysis in Haiti: dream or reality?

According to the World Health Organization reports, nowadays burden of chronic kidney diseases (CKD) is well documented. The high prevalence of noncommunicable diseases (NCD) such as hypertension, diabetes, and obesity, which are the main causes of CKD, is a big concern in the world health scenario. These NCD can progress slowly to end-stage renal disease (ESRD) and the low-middle income countries (LMIC) like Haiti are not left unscathed by this worldwide scourge. Several well-known public health issues prevalent in Haiti such as acute diarrheal infections, malaria, tuberculosis, cholera, and acquired immunodeficiency syndrome (AIDS), can also impair the function of the kidney. Dialysis, a form of renal replacement therapy (RRT), represents a life-saving therapy for all patients affected with impaired kidney. In Haiti, few patients have access to health insurance or disability financial support. Considering that seventy-two percent (72%) of Haitians live with less than USD 2 per day, survival with CKD can be quite stressful for them. Data on the weight of the dialysis and its management are scarce. Addressing the need for dialysis in Haiti is an important component in decision-making and planning processes in the health sector. This paper is intended to bring forth discussion on the use of this type of renal replacement therapy in Haiti: the past, the present, and the challenges it presents. We will also make some recommendations in order to manage this serious problem.