Childhood BMI trajectories and the risk of developing young adult-onset diabetes

Childhood BMI and other measures of body composition as a predictor of cardiometabolic non-communicable diseases in adulthood: a systematic review

OBJECTIVE

There is growing evidence that childhood malnutrition is associated with non-communicable diseases (NCD) in adulthood and that body composition mediates some of this association. This review aims to determine if childhood body composition can be used to predict later-life cardiometabolic NCD and which measures of body composition predicts future NCD.

DESIGN

Electronic databases were searched for articles where: children aged under 5 years had body composition measured; cardiometabolic health outcomes were measured a minimum of 10 years later.

SETTING

The databases Embase, Medline and Global Health were searched through July 2020.

PARTICIPANTS

Children aged under 5 years with a follow-up of minimum 10 years.

RESULTS

Twenty-nine studies met the inclusion criteria. Though a poor proxy measure of body composition, body mass index (BMI) was commonly reported (n 28, 97 %). 25 % of these studies included an additional measure (ponderal index or skinfold thickness). Few studies adjusted for current body size (n 11, 39 %).

CONCLUSIONS

Many studies reported that low infant BMI and high childhood BMI were associated with an increased risk of NCD-related outcomes in later life but no conclusions can be made about the exact timing of child malnutrition and consequent impact on NCD. Because studies focussed on BMI rather than direct measures of body composition, nothing can be said about which measures of body composition in childhood are most useful. Future research on child nutrition and long-term outcomes is urgently needed and should include validated body composition assessments as well as standard anthropometric and BMI measurements.

Obesity in late adolescence and incident type 1 diabetes in young adulthood

AIMS/HYPOTHESIS

Studies in children have reported an association between increased BMI and risk for developing type 1 diabetes, but evidence in late adolescence is limited. We studied the association between BMI in late adolescence and incident type 1 diabetes in young adulthood.

METHODS

All Israeli adolescents, ages 16-19 years, undergoing medical evaluation in preparation for mandatory military conscription between January 1996 and December 2016 were included for analysis unless they had a history of dysglycaemia. Data were linked with information about adult onset of type 1 diabetes in the Israeli National Diabetes Registry. Weight and height were measured at study entry. Cox proportional models were applied, with BMI being analysed both as a categorical and as a continuous variable.

RESULTS

There were 777 incident cases of type 1 diabetes during 15,819,750 person-years (mean age at diagnosis 25.2±3.9 years). BMI was associated with incident type 1 diabetes. In a multivariable model adjusted for age, sex and sociodemographic variables, the HRs for type 1 diabetes were 1.05 (95% CI 0.87, 1.27) for the 50th-74th BMI percentiles, 1.41 (95% CI 1.11, 1.78) for the 75th-84th BMI percentiles, 1.54 (95% CI 1.23, 1.94) for adolescents who were overweight (85th-94th percentiles), and 2.05 (95% CI 1.58, 2.66) for adolescents with obesity (≥95th percentile) (reference group: 5th-49th BMI percentiles). One increment in BMI SD was associated with a 25% greater risk for incidence of type 1 diabetes (HR 1.25, 95% CI 1.17, 1.32).

CONCLUSIONS

Excessively high BMI in otherwise healthy adolescents is associated with increased risk for incident type 1 diabetes in early adulthood.

Obesity in Patients with Type 1 Diabetes: Links, Risks and Management Challenges

Obesity affects large numbers of patients with type 1 diabetes (T1D) across their lifetime, with rates ranging between 2.8% and 37.1%. Patients with T1D and obesity are characterized by the presence of insulin resistance, of high insulin requirements, have a greater cardiometabolic risk and an enhanced risk of developing chronic complications when compared to normal-weight persons with T1D. Dual treatment of obesity and T1D is challenging and no specific guidelines for improving outcomes of both glycemic control and weight management have been established for this population. Nevertheless, although evidence is scarce, a comprehensive approach based on a balanced hypocaloric diet, physical activity and cognitive behavioral therapy by a multidisciplinary team, expert in both obesity and diabetes, remains as the best clinical practice. However, weight loss responses with lifestyle changes alone are limited, so in the "roadmap" of the treatment of obesity in T1D, it will be helpful to include anti-obesity pharmacotherapy despite at present there is a lack of evidence since T1D patients have been excluded from anti-obesity drug clinical trials. In case of severe obesity, bariatric surgery has proven to be of benefit in obtaining a substantial and long-term weight loss and reduction in cardiovascular risk. The near future looks promising with the development of new and more effective anti-obesity treatments and strategies to improve insulin resistance and oxidative stress. Advances in precision medicine may help individualize and optimize the medical management and care of these patients. This review, by gathering current evidence, highlights the need of solid knowledge in all facets of the treatment of patients with obesity and T1D that can only be obtained through high quality well-designed studies.

Current understandings of the pathogenesis of type 1 diabetes: Genetics to environment

Type 1 diabetes (T1D) is an autoimmune disease that usually strikes early in life, but can affect individuals at almost any age. It is caused by autoreactive T cells that destroy insulin-producing beta cells in the pancreas. Epidemiological studies estimate a prevalence of 1 in 300 children in the United States with an increasing incidence of 2%-5% annually worldwide. The daily responsibility, clinical management, and vigilance required to maintain blood sugar levels within normal range and avoid acute complications (hypoglycemic episodes and diabetic ketoacidosis) and long term micro- and macro-vascular complications significantly affects quality of life and public health care costs. Given the expansive impact of T1D, research work has accelerated and T1D has been intensively investigated with the focus to better understand, manage and cure this condition. Many advances have been made in the past decades in this regard, but key questions remain as to why certain people develop T1D, but not others, with the glaring example of discordant disease incidence among monozygotic twins. In this review, we discuss the field’s current understanding of its pathophysiology and the role of genetics and environment on the development of T1D. We examine the potential implications of these findings with an emphasis on T1D inheritance patterns, twin studies, and disease prevention. Through a better understanding of this process, interventions can be developed to prevent or halt it at early stages.

Rate of change in body mass index at different ages during childhood and adult obesity risk

BACKGROUND

Childhood body mass index (BMI) predicts adult obesity. How growth trajectories during childhood relate to adult obesity risk is not well defined.

OBJECTIVE

We aimed to characterize BMI growth trajectories from childhood to midlife and to examine the associations between BMI growth rates at childhood age points and adult obesity risk.

METHODS

The longitudinal study included 2732 participants with repeated BMI measurements from childhood (4-19 y) to adulthood (20-51 y). A random-effects model was used to construct BMI growth curves by race and sex. Model-estimated levels and linear growth rates of BMI were linked to adult obesity in separate multivariable logistic regression models at individual childhood age points.

RESULTS

BMI followed cubic growth curves. Childhood BMI linear slope estimates were higher in adults with obesity than in adults without obesity (P < 0.001). The association between childhood BMI growth rate and adult obesity was significantly higher in puberty and postpuberty (12-19 y) than in early childhood (4-11 y) with a peak at age 14 (odds ratio = 3.1 and 95% confidence interval, 2.7-3.5).

CONCLUSIONS

Rates of change in BMI at different childhood ages are differentially associated with adult obesity. Puberty and postpuberty are crucial periods for the development of obesity in later life.

Trajectories of childhood BMI and adult diabetes: the Bogalusa Heart Study

AIMS/HYPOTHESIS

The aim of this study was to characterise longitudinal profiles of BMI from childhood and to examine the impact of level-independent childhood BMI trajectories on adult type 2 diabetes.

METHODS

The longitudinal cohort consisted of 2449 adults (1613 white and 836 black) who had their BMI measured between four and 15 times from childhood (4-19 years) to adulthood (20-51 years) and fasting glucose measured in adulthood. Model-estimated levels and linear slopes of BMI at childhood age points were calculated in 1-year intervals using growth-curve parameters and their first derivatives, respectively.

RESULTS

BMI from childhood to adulthood fit cubic growth curves; linear and non-linear curve parameters differed significantly between race-sex groups. BMI showed race and sex differences from 15 years onwards. Individuals with hyperglycaemia had higher long-term BMI levels than those who were normoglycaemic in race-sex groups. Linear and non-linear slope parameters of BMI differed consistently and significantly between adult hyperglycaemia groups. The OR of childhood BMI levels for ages 4-19 years was 1.45-1.83 (p < 0.001 for all) for adult hyperglycaemia after adjustment for confounders. Level-adjusted linear slopes of BMI at ages 10-19 years showed significantly positive associations with adult hyperglycaemia (OR 1.17-1.50, p < 0.01 for all). The associations of childhood BMI linear slopes with adult hyperglycaemia were not significant during the age period 5-9 years. The trends in these associations were consistent across race-sex groups.

CONCLUSIONS/INTERPRETATION

These observations indicate that childhood BMI trajectories have a significant impact on adult diabetes, independent of BMI levels. The adolescence age period is a crucial window for the development of diabetes in later life, which has implications for early-life prevention.

DATA AVAILABILITY

All data and materials are publicly available at the National Heart, Lung, and Blood Institute (NHLBI) Biologic Specimen and Data Repository and can be accessed at https://biolincc.nhlbi.nih.gov/studies/bhs .

Infant body mass index peak and early childhood cardio-metabolic risk markers in a multi-ethnic Asian birth cohort

Background

: Infant body mass index (BMI) peak has received much interest recently as a potential predictor of future obesity and metabolic risk. No studies, however, have examined infant BMI peak in Asian populations, in whom the risk of metabolic disease is higher.

Methods

: We utilized data among 1020 infants from a mother-offspring cohort, who were Singapore citizens or permanent residents of Chinese, Malay or Indian ethnicity with homogeneous parental ethnic backgrounds, and did not receive chemotherapy, psychotropic drugs or have diabetes mellitus. Ethnicity was self-reported at recruitment and later confirmed using genotype analysis. Subject-specific BMI curves were fitted to infant BMI data using natural cubic splines with random coefficients to account for repeated measures in each child. We estimated characteristics of the child's BMI peak [age and magnitude at peak, average pre-peak velocity (aPPV)]. Systolic (SBP) and diastolic blood pressure (DBP), BMI, sum of skinfolds (SSF) and fat-mass index (FMI) were measured during a follow-up visit at age 48 months. Weighted multivariable linear regression was used to assess the predictors (maternal BMI, gestational weight gain, ethnicity, infant sex, gestational age, birthweight-for-gestational age and breastfeeding duration) of infant BMI peak and its associations with outcomes at 48 months. Comparisons between ethnicities were tested using Bonferroni post-hoc correction.

Results

: Of 1020 infants, 80.5% were followed up at the 48-month visit. Mean (SD) BMI, SSF and FMI at 48 months were 15.6 (1.8) kg/m 2 , 16.5 (5.3) mm and 3.8 (1.3) kg/m 2 , respectively. Mean (SD) age at peak BMI was 6.0 (1.6) months, with a magnitude of 17.2 (1.4) kg/m 2 and pre-peak velocity of 0.7 (0.3) kg/m 2 /month. Compared with Chinese infants, the peak occurred later in Malay {B [95% confidence interval (CI): 0.64 mo (0.36, 0.92)]} and Indian infants [1.11 mo (0.76, 1.46)] and was lower in magnitude in Indian infants [-0.45 kg/m 2 (-0.69, -0.20)]. Adjusting for maternal education, BMI, gestational weight gain, ethnicity, infant sex, gestational age, birthweight-for-gestational-age and breastfeeding duration, higher peak and aPPV were associated with greater BMI, SSF and FMI at 48 months. Age at peak was positively associated with BMI at 48 months [0.15 units (0.09, 0.22)], whereas peak magnitude was associated with SBP [0.17 units (0.05, 0.30)] and DBP at 48 months [0.10 units (0.01, 0.22)]. Older age and higher magnitude at peak were associated with increased risk of overweight at 48 months [Relative Risk (95% CI): 1.35 (1.12-1.62) for age; 1.89 (1.60-2.24) for magnitude]. The associations of BMI peak with BMI and SSF at 48 months were stronger in Malay and Indian children than in Chinese children.

Conclusions

: Ethnic-specific differences in BMI peak characteristics, and associations of BMI peak with early childhood cardio-metabolic markers, suggest an important impact of early BMI development on later metabolic outcomes in Asian populations.

Prenatal phthalate exposure and 8-isoprostane among Mexican-American children with high prevalence of obesity

Oxidative stress has been linked to many obesity-related conditions among children including cardiovascular disease, diabetes mellitus and hypertension. Exposure to environmental chemicals such as phthalates, ubiquitously found in humans, may also generate reactive oxygen species and subsequent oxidative stress. We examined longitudinal changes of 8-isoprostane urinary concentrations, a validated biomarker of oxidative stress, and associations with maternal prenatal urinary concentrations of phthalate metabolites for 258 children at 5, 9 and 14 years of age participating in a birth cohort residing in an agricultural area in California. Phthalates are endocrine disruptors, and in utero exposure has been also linked to altered lipid metabolism, as well as adverse birth and neurodevelopmental outcomes. We found that median creatinine-corrected 8-isoprostane concentrations remained constant across all age groups and did not differ by sex. Total cholesterol, systolic and diastolic blood pressure were positively associated with 8-isoprostane in 14-year-old children. No associations were observed between 8-isoprostane and body mass index (BMI), BMI Z-score or waist circumference at any age. Concentrations of three metabolites of high molecular weight phthalates measured at 13 weeks of gestation (monobenzyl, monocarboxyoctyl and monocarboxynonyl phthalates) were negatively associated with 8-isoprostane concentrations among 9-year olds. However, at 14 years of age, isoprostane concentrations were positively associated with two other metabolites (mono(2-ethylhexyl) and mono(2-ethyl-5-carboxypentyl) phthalates) measured in early pregnancy. Longitudinal data on 8-isoprostane in this pediatric population with a high prevalence of obesity provides new insight on certain potential cardiometabolic risks of prenatal exposure to phthalates.

Maximum BMI and microvascular complications in a cohort of Japanese patients with type 2 diabetes: the Japan Diabetes Complications Study

AIMS

The aim of this study was to examine the associations between possible indices of obesity based on information on weight history and the incidence of microvascular complications.

METHODS

A cohort of individuals with type 2 diabetes from 59 institutes in Japan was followed for 8years. Patients were classified into three categories according to weight at entrance and past maximum weight: normal (BMI at baseline <25kg/m(2) and maximum BMI <25kg/m(2)), past obesity (BMI at baseline <25kg/m(2) and maximum BMI ≥25kg/m(2)), and current obesity (BMI at baseline ≥25kg/m(2)) groups. The outcomes were diabetic retinopathy and overt nephropathy.

RESULTS

BMI at maximum and baseline of the 1809 patients was 26.5±3.5 and 23.1±3.0kg/m(2) (p<0.01), respectively (23.0±1.6 and 20.6±1.9kg/m(2) for normal, 27.4±2.0 and 22.8±1.4kg/m(2) for past obesity, and 30.1±2.9 and 27.0±1.8kg/m(2) for current obesity). The hazard ratios of past and current obesity compared to normal were 1.92 (95% CI, 1.08-3.41; p=0.03) and 2.21 (1.16-4.22; p=0.02), respectively, for overt nephropathy and 1.38 (1.05-1.83; p=0.02) and 1.64 (1.18-2.28; p<0.01), respectively, for diabetic retinopathy after adjustment for confounders.

CONCLUSIONS

Past obesity as well as current obesity were associated with increased risks of microvascular complications. Further identification of high-risk populations may be possible by classifying normal weight patients by past obesity.

High birth weights but not excessive weight gain prior to manifestation are related to earlier onset of diabetes in childhood: 'accelerator hypothesis' revisited

AIMS/HYPOTHESIS

Aim of this study was to test Wilkin's 'accelerator hypothesis': whether excessive weight gain accelerates the onset of type 1 diabetes.

SUBJECTS AND METHODS

Anthropometric birth data of 1117 children who developed diabetes between 1988 and April 2013 were compared with those of a sex, age, and gestational age matched, contemporary regional control group (n = 54 344). Cases were divided into three manifestation groups (G1:0-4.9 yr, G2:5-9.9 yr, and G3: 10-20 yr). Furthermore, growth data of 540 children with diabetes were compared with controls (n = 134 249) in pre-, peri-, and post-onset intervals (interval: 1-6). Also, correlation of age at onset and body mass index (BMI) standard deviation score (SDS) at this point of time were examined.

RESULTS

Cases had significantly higher SDSs for birth weight when compared with controls (boys: p = 0.007, girls: p = 0.002). Children with early manifestation had the highest mean of birth weight SDS (G1>G2>G3), (p = 0.22, adjusted r(2) = 0.001). BMI SDS trend curves of cases are slightly higher compared with those of the healthy controls. This was only significant in years after diagnosis (interval 6, p < 0.000). Cases did not show excessive weight gain in any of the examined intervals before the onset of diagnosis (interval 1-3). One year after diagnosis, we found an inverse correlation between age at diagnosis and BMI SDS at diabetes manifestation. The youngest children at diagnosis (G1) had the lowest BMI SDS at manifestation and vice versa (G1<G2<G3, p = 0.06).

CONCLUSIONS

Our data do not support the 'accelerator hypothesis'. There was no sign of excessive weight gain before manifestation. Discrepant results from other studies could be due to non-age-adjusted controls.

Association between infancy BMI peak and body composition and blood pressure at age 5-6 years

INTRODUCTION

The development of overweight is often measured with the body mass index (BMI). During childhood the BMI curve has two characteristic points: the adiposity rebound at 6 years and the BMI peak at 9 months of age. In this study, the associations between the BMI peak and body composition measures and blood pressure at age 5-6 years were investigated.

METHODS

Measurements from the Amsterdam Born Children and their Development (ABCD) study were available for this study. Blood pressure (systolic and diastolic) and body composition measures (BMI, waist-to-height ratio, fat percentage) were gathered during a health check at about 6 years of age (n = 2822). All children had multiple BMI measurements between the 0-4 years of age. For boys and girls separately, child-specific BMI peaks were extracted from mixed effect models. Associations between the estimated BMI peak and the health check measurements were analysed with linear models. In addition, we investigated the potential use of the BMI at 9 months as a surrogate measure for the magnitude of the BMI peak.

RESULTS

After correction for the confounding effect of fetal growth, both timing and magnitude of the BMI peak were significantly and positively associated (p<0.001) with all body composition measures at the age of 5-6 years. The BMI peak showed no direct association with blood pressure at the age 5-6 year, but was mediated by the current BMI. The correlation between the magnitude of the BMI peak and BMI at 9 months was approximately 0.93 and similar associations with the measures at 5-6 years were found.

CONCLUSION

The magnitude of the BMI peak was associated with body composition measures at 5-6 years of age. Moreover, the BMI at 9 months could be used as surrogate measure for the magnitude of the BMI peak.

Adiponectin and leptin trajectories in Mexican-American children from birth to 9 years of age

OBJECTIVES

To address molecular mechanisms underlying obesity development, we examined patterns of critical metabolism-related hormones, adiponectin and leptin (adipokines), over childhood.

SUBJECTS AND DESIGN

Plasma adiponectin and leptin were measured in 80 Mexican-American children at birth and again at 2, 5, and 9 years from the ongoing prospective cohort followed by the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS). We used a mixture modeling approach to identify patterns in adipokine trajectories from birth to 9 years.

RESULTS

Leptin was positively related to child body size within all ages, however adiponectin had inverse and weaker associations with BMI at 2, 5, and 9 years. Correlations between adipokine levels over the 0-2, 2-5, and 5-9-year periods increased for both leptin (r = 0.06, 0.31 and 0.62) and adiponectin (r = 0.25, 0.41 and 0.46). Our mixture modeling approach identified three trajectory clusters for both leptin (1L [slowly-rising], 2L [rapidly-rising], and 3L [stable]) and adiponectin (1A [steep-dropping and rebounding], 2A [moderately-dropping], and 3A [stable]). While leptin groups were most separated over the 2-9-year period, adiponectin trajectories displayed greatest heterogeneity from birth to 2 years. Children in the rapidly-rising 2L group had highest BMI and waist circumference at 9 years. Further, children with greater birth weight had increased odds of belonging to this high risk group (OR = 1.21 95% CI 1.03, 1.43, compared to stable group 3L). Children whose mothers consumed more sugar-sweetened beverages during pregnancy were at risk of being in the steep-dropping 1A group (OR = 1.08, 95% CI 1.01, 1.17, compared to stable group 3A).

CONCLUSION

Our results highlight developmental differences in leptin and adiponectin over the childhood period. Leptin closely reflects child body size however factors affecting adiponectin and long-term consequences of its changes over infancy need to be further explored.

Birth weight influences the clinical phenotype and the metabolic control of patients with type 1 diabetes (T1D)

BACKGROUND

High birth weight has been related to an increased risk of type 1 diabetes (T1D), while suboptimal birth weight (both high and low) has been related to obesity, insulin resistance and type 2 diabetes. Insulin resistance, as a consequence of poor metabolic control, has been described in T1D patients. The aims of the study were to analyse the distribution of birth size for gestational age in a large group of T1D patients and to investigate the effect of birth weight on clinical phenotype.

METHODS

Six-hundred two Caucasian T1D patients were evaluated. Small for gestational age (SGA) and large for gestational age (LGA) were defined as birth weight at <3rd percentile and >97th percentile for gestational age, respectively. Birth weights between the 3rd and 97th percentiles were defined as appropriate for gestational age. The clinical characteristics of small, appropriate for gestational age and large were compared. Multivariable linear regression models were fitted to evaluate the independent effects of birth weight and other covariates (age at T1D onset, gender and T1D duration) on different clinical outcomes (body mass index, HbA(1c), insulin requirement, high-density lipoprotein cholesterol and triglycerides).

RESULTS

Thirteen subjects (2.16%) were small (SGA), and 39 (6.48%) were large (LGA). Daily insulin requirement (U/kg/day) was significantly higher in SGA, while body mass index and HbA(1c) were increased in LGA. Multivariable linear regression showed a significant negative effect of birth weight on daily insulin requirement (p < 0.001).

CONCLUSIONS

Suboptimal birth weight (both high and low) in T1D patients seems to be associated with clinical characteristics suggestive of insulin resistance.

Programming research: where are we and where do we go from here?

Convincing evidence has accumulated to show that both pre- and postnatal nutrition preprogram long-term health, well-being, and performance until adulthood and old age. There is a very large potential in the application of this knowledge to promote public health. One of the prerequisites for translational application is to strengthen the scientific evidence. More extensive knowledge is needed (eg, on effect sizes of early life programming in contemporary populations, on specific nutritional exposures, on sensitive time periods in early life, on precise underlying mechanisms, and on potential effect differences in subgroups characterized by, eg, genetic predisposition or sex). Future programming research should aim at filling the existing gaps in scientific knowledge, consider the entire lifespan, address socioeconomic issues, and foster innovation. Research should aim at results suitable for translational application (eg, by leading to health-promoting policies and evidence-based dietary recommendations in the perinatal period). International collaboration and a close research partnership of academia, industry, and small and medium enterprises may strengthen research and innovative potential enhancing the likelihood of translational application. The scientific know-how and methodology available today allow us to take major steps forward in the near future; hence, research on nutritional programming deserves high priority.

Longitudinal study of childhood adiposity and the risk of developing components of metabolic syndrome-the Da Qing children cohort study

Childhood adiposity is increasingly recognized as a significant predictor of cardiometabolic risks in later life. The aim of this study was to investigate factors associated with longitudinal changes in weight during childhood and the development of metabolic disease risk factors. Four hundred twenty-four children from DaQing city, China, were recruited at 5 y old and followed up for 5 y. Birth weight, television (TV) viewing time at 5 y old, blood pressure, anthropometric measurements, fasting plasma insulin (FI), and triglycerides (TG) levels were measured at 5 and 10 y old. Both birth weight and TV viewing time at 5 y old significantly correlated with percentage of ideal weight for height (WFH) at 5 y old (WFH5; p = 0.0032 and p = 0.01), but only TV time was significantly correlated with WFH at 10 y old (WFH10; p < 0.0001). Blood pressures, FI, homeostasis model assessment for insulin resistance (HOMA-IR), and TG at 10 y old were significantly greater in those children who had greater change in WFH from 5 to 10 y old (ΔWFH). We concluded that TV viewing time was the stronger determinant of later childhood adiposity. A greater ΔWFH was associated with increased cardiometabolic risk factors at 10 y old.

Genetic and environmental factors influencing BMI development from adolescence to young adulthood

BMI increases progressively from adolescence to young adulthood. The aims of the present study were firstly, to investigate the extent to which genetic and environmental influences account for differences in BMI trajectories during this period, and secondly to examine whether boys and girls show divergences in these influences, as their BMI normally start differing across adolescence. The study sample consisted of 4,915 monozygotic and like- and unlike-sex dizygotic twins, born between 1975 and 1979. Data on BMI was gathered when twins were on average 16.1, 17.1, 18.6 and 24.4 years old. Genetic and environmental influences on the BMI trajectories were modeled using a latent growth curve approach. The results showed that the heritability of BMI decreased slightly after the adolescence period, from ≈ 80 to 70%. BMI transition from adolescence to young adulthood was best described by a quadratic trajectory that was highly accounted (61.7-86.5%) for by additive genetic influences. Genetic influences on BMI level showed a low correlation with those on the trend in BMI with age indicating that different sets of genes underlie the change of BMI during this period. Importantly, the analyses also evidenced that different genetic and environmental influences may underlie boys and girls evolution. In conclusion, our results suggested specific genetic influences accounting for the BMI rate-of-change from adolescence to young adulthood. This indicates that the specific genes behind BMI level may not be the same as the genes affecting BMI change which should be taken into account in further efforts to identify these genes.

Association between childhood obesity and subsequent Type 1 diabetes: a systematic review and meta-analysis

AIMS

To review and synthesize the published evidence on the possible association between childhood obesity and the subsequent risk of Type 1 diabetes.

METHODS

The PubMed database was systematically searched for studies using childhood obesity, BMI or %weight-for-height as the exposure variable and subsequent Type 1 diabetes as the outcome. Studies were only included if assessment of obesity preceded the diagnosis of Type 1 diabetes.

RESULTS

Eight case-control studies and one cohort study were included, comprising a total of 2658 cases. Of these nine studies, seven reported a significant association between childhood obesity, BMI or %weight-for-height and increased risk for Type 1 diabetes. Meta-analysis of the four studies that reported childhood obesity as a categorical exposure produced a pooled odds ratio of 2.03 (95% CI 1.46-2.80) for subsequent Type 1 diabetes; however, in those studies, age at obesity assessment varied from age 1 to 12 years. A dose-response relationship was supported by a continuous association between childhood BMI and subsequent Type 1 diabetes in a meta-analysis of five studies (pooled odds ratio 1.25 (95%CI 1.04-1.51) per 1 sd higher BMI).

CONCLUSION

There is overall evidence for an association between childhood obesity, or higher BMI, and increased risk of subsequent Type 1 diabetes. Several theories have been proposed for a causal relationship. Reduction in Type 1 diabetes should be considered as a potential additional benefit of preventing childhood obesity.

Long-term impact of overweight and obesity in childhood and adolescence on morbidity and premature mortality in adulthood: systematic review

BACKGROUND AND OBJECTIVE

The last systematic review on the health consequences of child and adolescent obesity found little evidence on consequences for adult health. The present study aimed to summarize evidence on the long-term impact of child and adolescent obesity for premature mortality and physical morbidity in adulthood.

METHODS

Systematic review with evidence searched from January 2002 to June 2010. Studies were included if they contained a measure of overweight and/or obesity between birth and 18 years (exposure measure) and premature mortality and physical morbidity (outcome) in adulthood.

RESULTS

Five eligible studies examined associations between overweight and/or obesity, and premature mortality: 4/5 found significantly increased risk of premature mortality with child and adolescent overweight or obesity. All 11 studies with cardiometabolic morbidity as outcomes reported that overweight and obesity were associated with significantly increased risk of later cardiometabolic morbidity (diabetes, hypertension, ischaemic heart disease, and stroke) in adult life, with hazard ratios ranging from 1.1-5.1. Nine studies examined associations of child or adolescent overweight and obesity with other adult morbidity: studies of cancer morbidity were inconsistent; child and adolescent overweight and obesity were associated with significantly increased risk of later disability pension, asthma, and polycystic ovary syndrome symptoms.

CONCLUSIONS

A relatively large and fairly consistent body of evidence now demonstrates that overweight and obesity in childhood and adolescence have adverse consequences on premature mortality and physical morbidity in adulthood.

Impact of early psychosocial factors (childhood socioeconomic factors and adversities) on future risk of type 2 diabetes, metabolic disturbances and obesity: a systematic review

Background

Psychological factors and socioeconomic status (SES) have a notable impact on health disparities, including type 2 diabetes risk. However, the link between childhood psychosocial factors, such as childhood adversities or parental SES, and metabolic disturbances is less well established. In addition, the lifetime perspective including adult socioeconomic factors remains of further interest.

We carried out a systematic review with the main question if there is evidence in population- or community-based studies that childhood adversities (like neglect, traumata and deprivation) have considerable impact on type 2 diabetes incidence and other metabolic disturbances. Also, parental SES was included in the search as risk factor for both, diabetes and adverse childhood experiences. Finally, we assumed that obesity might be a mediator for the association of childhood adversities with diabetes incidence. Therefore, we carried out a second review on obesity, applying a similar search strategy.

Methods

Two systematic reviews were carried out. Longitudinal, population- or community-based studies were included if they contained data on psychosocial factors in childhood and either diabetes incidence or obesity risk.

Results

We included ten studies comprising a total of 200,381 individuals. Eight out of ten studies indicated that low parental status was associated with type 2 diabetes incidence or the development of metabolic abnormalities. Adjustment for adult SES and obesity tended to attenuate the childhood SES-attributable risk but the association remained. For obesity, eleven studies were included with a total sample size of 70,420 participants. Four out of eleven studies observed an independent association of low childhood SES on the risk for overweight and obesity later in life.

Conclusions

Taken together, there is evidence that childhood SES is associated with type 2 diabetes and obesity in later life. The database on the role of psychological factors such as traumata and childhood adversities for the future risk of type 2 diabetes or obesity is too small to draw conclusions. Thus, more population-based longitudinal studies and international standards to assess psychosocial factors are needed to clarify the mechanisms leading to the observed health disparities.

Infant feeding and the risk of type 1 diabetes

Type 1 diabetes is generally considered to be a chronic, immune-mediated disease with a subclinical prodrome during which beta cell autoimmunity becomes overt disease at a variable rate in genetically susceptible individuals. Accumulated evidence supports a critical role of environmental factors in its development. Prospective birth cohort studies show that the first signs of beta cell autoimmunity may be initiated during the first year of life. This implies that risk factors for beta cell autoimmunity and type 1 diabetes must be operative in infancy. Early nutrition provides essential exogenous exposures in that period. This article discusses the role of factors related to infant nutrition in the development of beta cell autoimmunity and type 1 diabetes and the potential mechanistic pathways involved. So far, no specific dietary factor has been shown to be an unequivocal risk factor for beta cell autoimmunity or type 1 diabetes, and there are a number of contradictory observations with regard to the effect of various foods. This may reflect geographic and cultural differences in infant-feeding practices. Most studies suggest that the early introduction of complex foreign proteins may be a risk factor for beta cell autoimmunity, and a pilot intervention trial has implied that weaning to a highly hydrolyzed formula may decrease the risk of beta cell autoimmunity. Lack of vitamin D supplementation and accelerated growth might increase the risk of type 1 diabetes. Additional work, which includes the application of modern approaches such as metabolomics and epigenomics, is needed to discern the contribution of dietary factors in infancy to the diabetic disease process.