Genetic vulnerability to diabetes and obesity: does education offset the risk?

Challenges in studying the interplay of genes and environment. A study of childhood financial distress moderating genetic predisposition for peak smoking

Smoking is one of the leading causes of preventable disease and death in the U.S., and it is strongly influenced both by genetic predisposition and childhood adversity. Using polygenic indices (PGIs) of predisposition to smoking, we evaluate whether childhood financial distress (CFD; a composite measure of financial adversity) moderates genetic risk in explaining peak-cigarette consumption in adulthood. Using the Health and Retirement Study (HRS), we find a substantial reduction in the relationship between genetic risk and peak smoking for those who did not suffer financial adversity in childhood. Among adult smokers who grew up in high-CFD households, a one standard deviation higher PGI is associated with 2.9 more cigarettes smoked per day at peak. By contrast, among smokers who grew up in low-CFD households, this gradient is reduced by 37 percent (or 1.1 fewer). These results are robust to controlling for a host of prime confounders. By contrast, we find no evidence of interactions between the PGI and typical measures of childhood SES such as parental education - a null result that we replicate in the Wisconsin Longitudinal Study (WLS) and the English Longitudinal Study of Aging (ELSA). This suggests the role of childhood financial distress in the relationship with peak smoking is distinct from that of low childhood SES, with high CFD potentially reflecting more acute distress than do measures of low childhood SES. Our evidence also suggests low childhood SES is a weaker proxy for acute distress, providing an alternative explanation for the childhood SES null result.

Mortality in Women across the FMR1 CGG Repeat Range: The Neuroprotective Effect of Higher Education

Higher education has been shown to have neuroprotective effects, reducing the risk of Alzheimer's and Parkinson's diseases, slowing the rate of age-related cognitive decline, and is associated with lower rates of early mortality. In the present study, the association between higher education, fragile X messenger ribonucleoprotein 1 (FMR1) cytosine-guanine-guanine (CGG) repeat number, and mortality before life expectancy was investigated in a population cohort of women born in 1939. The findings revealed a significant interaction between years of higher education and CGG repeat number. Counter to the study's hypothesis, the effects of higher education became more pronounced as the number of CGG repeats increased. There was no effect of years of higher education on early mortality for women who had 25 repeats, while each year of higher education decreased the hazard of early mortality by 8% for women who had 30 repeats. For women with 41 repeats, the hazard was decreased by 14% for each additional year of higher education. The interaction remained significant after controlling for IQ and family socioeconomic status (SES) measured during high school, as well as factors measured during adulthood (family, psychosocial, health, and financial factors). The results are interpreted in the context of differential sensitivity to the environment, a conceptualization that posits that some people are more reactive to both negative and positive environmental conditions. Expansions in CGG repeats have been shown in previous FMR1 research to manifest such a differential sensitivity pattern.

Education counteracts the genetic risk of Alzheimer's disease without an interaction effect

Background

Alzheimer's disease (AD) is a major cause of disability and mortality in older adults. This study aimed to investigate the association of AD with education and genetic factors.

Methods

We conducted a prospective cohort study using data from the UK Biobank. Genetic risk was assessed using a polygenic risk score for AD. The educational level was categorized as either low, intermediate, or high. AD was defined using the International Classification of Diseases and Related Health Problems, 10th revision. Logistic regression models were used to investigate the independent and combined effects of genetic factors and educational levels on the risk of AD.

Results

We included 318,535 participants in this study (age: 56.53 ± 8.09 years; male: 44.81%). Compared with a low genetic risk, a high genetic risk was associated with a significantly greater risk of AD (OR = 7.09, 95% CI: 6.09-8.26). A high educational level was associated with a 30% lower risk of AD compared with a low educational level (OR = 0.70, 95% CI: 0.60-0.81). Combining genetic risk and education categories, individuals with a low genetic risk and high educational level had a more than 90% (OR = 0.09, 95% CI: 0.05-0.16) lower risk of AD compared to those with a high genetic risk and low educational level. There was no significant interaction between genetic risk and educational level regarding AD risk (p for interaction = 0.359).

Conclusion

Education counteracts the genetic risk of AD, without an interaction effect. Increasing education to reduce the incidence of AD is of same importance across individuals with different genetic risk.

The effect of college degree attainment on neurodegenerative symptoms in genetically at-risk women

Using longitudinal data, the present study examined the association between college degree attainment and the manifestation of neurodegenerative symptoms among women (n = 93) at elevated genetic risk. The neurodegenerative symptoms investigated in this study are due to FXTAS (Fragile X-associated Tremor/Ataxia Syndrome), a condition with onset after age 50. Those at risk for FXTAS have a mutation of a single gene found on the X chromosome. FXTAS is characterized by intention tremor, gait ataxia, executive function deficits, memory issues, and neuropathy. College degree attainment has been shown to provide neuroprotective effects in the general population, delaying the development of neurodegenerative conditions such as Alzheimer's disease. For this reason, college degree attainment is a potentially salient resource for those at risk of FXTAS. The results of the present research indicated significantly more severe FXTAS symptoms in women who did not attain a college degree as compared with those who were college graduates, although the two groups were similar in age, genetic risk, household income, health behaviors, and general health problems. Furthermore, symptoms in those who did not attain a college degree worsened over the 9-year study period at a significantly faster rate than the college graduates. The association between college degree attainment and FXTAS symptoms was significantly mediated by depression, which was lower among the graduates than those who did not attain a college degree. Thus, the present research is an example of how a sociodemographic factor can mitigate neurodegenerative conditions in genetically at-risk adults.

Socioeconomic inequities in diet quality among a nationally representative sample of adults living in Canada: an analysis of trends between 2004 and 2015

BACKGROUND

Socioeconomic inequities in diet quality are stable or widening in the United States; however, these trends have not been well characterized in other nations. Moreover, purpose-developed indices of inequities that can provide a more comprehensive and precise perspective of trends in absolute and relative dietary gaps and gradients using multiple indicators of socioeconomic position (SEP) have not yet been used, and can inform strategies to narrow dietary inequities.

OBJECTIVES

We quantified nationally representative trends in absolute and relative gaps and gradients in diet quality between 2004 and 2015 according to 3 indicators of SEP among adults in Canada.

METHODS

Adults (≥18 y old) who participated in the nationally representative, cross-sectional Canadian Community Health Survey-Nutrition in 2004 (n = 20,880) or 2015 (n = 13,970) were included. SEP was classified using household income (quintiles), education (5 categories), and neighborhood deprivation (quintiles). Dietary intake data from 24-h recalls were used to derive Healthy Eating Index-2015 (HEI-2015) scores. Dietary inequities were quantified using absolute and relative gaps (between the most and least disadvantaged) and absolute [Slope Index of Inequality (SII)] and relative gradients (Relative Index of Inequality). Overall and sex-stratified multivariable linear regression and generalized linear models examined trends in HEI-2015 scores between 2004 and 2015.

RESULTS

Mean HEI-2015 scores improved from 55.3 to 59.0 (maximum: 100); however, these trends were not consistently equitable. Whereas inequities in HEI-2015 scores were stable in the total population and in females, the absolute gap [from 1.60 (95% CI: 0.09, 3.10) to 4.27 (95% CI: 2.20, 6.34)] and gradient [from SII = 2.09 (95% CI: 0.45, 3.73) to SII = 4.84 (95% CI: 2.49, 7.20)] in HEI-2015 scores for household income, and the absolute gradient for education [from SII = 8.06 (95% CI: 6.41, 9.71) to SII = 10.52 (95% CI: 8.73, 12.31)], increased in males.

CONCLUSIONS

Absolute and relative gaps and gradients in overall diet quality remained stable or widened between 2004 and 2015 among adults in Canada.

Associations of Genetic Factors, Educational Attainment, and Their Interaction With Kidney Function Outcomes

Both genetic predisposition and low educational attainment (EA) are associated with higher risk of chronic kidney disease. We examined the interaction of EA and genetic risk in kidney function outcomes. We included 3,597 participants from the Prevention of Renal and Vascular End-Stage Disease Cohort Study, a longitudinal study in a community-based sample from Groningen, the Netherlands (median follow-up, 11 years; 1997–2012). Kidney function was approximated by obtaining estimated glomerular filtration rate (eGFR) from serum creatinine and cystatin C. Individual longitudinal linear eGFR trajectories were derived from linear mixed models. Genotype data on 63 single-nucleotide polymorphisms, with known associations with eGFR, were used to calculate an allele-weighted genetic score (WGS). EA was categorized into high, medium, and low. In ordinary least squares analysis, higher WGS and lower EA showed additive effects on reduced baseline eGFR; the interaction term was nonsignificant. In analysis of eGFR decline, the significant interaction term suggested amplification of genetic risk by low EA. Adjustment for known renal risk factors did not affect our results. This study presents the first evidence of gene-environment interaction between EA and a WGS for eGFR decline and provides population-level insights into the mechanisms underlying socioeconomic disparities in chronic kidney disease.

Self-determination theory interventions versus usual care in people with diabetes: a protocol for a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Existing self-management and behavioural interventions for diabetes vary widely in their content, and their sustained long-term effectiveness is uncertain. Autonomy supporting interventions may be a prerequisite to achieve 'real life' patient engagement and more long-term improvement through shared decision-making and collaborative goal setting. Autonomy supportive interventions aim to promote that the person with diabetes' motivation is autonomous meaning that the person strives for goals they themselves truly believe in and value. This is the goal of self-determination theory and guided self-determination interventions. Self-determination theory has been reviewed but without assessing both benefits and harms and accounting for the risk of random errors using trial sequential analysis. The guided self-determination has not yet been systematically reviewed. The aim of this protocol is to investigate the benefits and harms of self-determination theory-based interventions versus usual care in adults with diabetes.

METHODS/DESIGN

We will conduct the systematic review following The Cochrane Collaboration guidelines. This protocol is reported according to the PRISMA checklist. A comprehensive search will be undertaken in the CENTRAL, MEDLINE, EMBASE, LILACS, PsycINFO, SCI-EXPANDED, CINAHL, SSCI, CPCI-S and CPCI-SSH to identify relevant trials. We will include randomised clinical trials assessing interventions theoretically based on guided self-determination or self-determination theory provided face-to-face or digitally by any healthcare professional in any setting. The primary outcomes will be quality of life, mortality, and serious adverse events. The secondary will be diabetes distress, depressive symptoms and adverse events not considered serious. Exploratory outcomes will be glycated haemoglobin and motivation. Outcomes will be assessed at the end of the intervention and at maximum follow-up. The analyses will be performed using Stata version 16 and trial sequential analysis. Two authors will independently screen, extract data from and perform risk of bias assessment of included studies using the Cochrane risk of bias tool. Certainty of the evidence will be assessed by GRADE.

DISCUSSION

Self-determination theory interventions aim to promote a more autonomous patient engagement and are commonly used. It is therefore needed to evaluate the benefit and harms according to existing trials.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020181144.

The Relative Contributions of Socioeconomic and Genetic Factors to Variations in Body Mass Index Among Young Adults

In light of recent findings on the small proportion of variance in body mass index (BMI) explained by shared environment, and growing interests in the role of genetic susceptibility, we assessed the relative contribution of socioeconomic status (SES) and genome-wide polygenic score for BMI to explaining variation in BMI. Our final analytic sample included 4,918 White and 1,546 Black individuals from the US National Longitudinal Study of Adolescent to Adult Health Wave IV (2007-2008) who had complete measures on BMI, demographics, SES, genetic data, and health behaviors. We used ordinary least-squares regression to assess variation in log(BMI) as a function of the aforementioned predictors, independently and mutually adjusted. All analyses were stratified by race/ethnicity in the main analysis, and further by sex. The age-adjusted variation in log(BMI) was 0.055 among Whites and 0.066 among Blacks. The contribution of SES and polygenic score ranged from less than1% to 6% and from 2% to 8%, respectively, and majority of the variation (87%-96%) in log(BMI) remained unexplained. Differential distribution of socioeconomic resources, stressors, and buffers may interact to produce systematically larger variation in vulnerable populations. More understanding of the contribution of biological, genetic, and environmental factors, as well as stochastic elements, in diverse phenotypic variance is needed in population health sciences.

Living with diabetes and disadvantage: A qualitative, geographical case study

AIMS AND OBJECTIVES

To elucidate the experiences of people living with diabetes, residing in an urban diabetogenic area.

BACKGROUND

Community-level social and environmental factors have a role to play in the development of type 2 diabetes mellitus. Socio-economic deprivation; high obesity rates; high access to fast foods; and multiculturalism contribute to higher rates of diabetes in some geographical areas. However, there is a lack of research examining people's experiences of living with diabetes in diabetogenic areas. The word diabetogenic implies that the phenomenon of interest contributes to the development of diabetes.

DESIGN

Qualitative, geographical case study approach.

METHODS

A convenience sample of 17 people living with diabetes in a diabetogenic, low-socio-economic urban area participated in face-to-face, semi-structured interviews. Interviews were audio-recorded, transcribed and analysed thematically. This paper adheres to the COREQ guidelines.

FINDINGS

Four main themes were identified: 1. Diabetes fatalism: Inevitability and inertia; 2. Living with Inequity: Literacy and intersectionality; 3. Impersonal services: Intimidating and overwhelming; and, 4. Education in the community: Access and anecdotes.

CONCLUSIONS

This study has highlighted the need to develop local solutions for local problems. In this geographical area, solutions need to address generally lower health literacy, how the community would prefer to receive diabetes education and the issue of diabetes fatalism.

RELEVANCE TO CLINICAL PRACTICE

Findings from this study have highlighted a need to re-examine how diabetes education is delivered in communities that are already experiencing multiple disadvantages. There are research and practice connotations for how fatalism is positioned for people at high risk of developing diabetes.

A genetic sum score of risk alleles associated with body mass index interacts with socioeconomic position in the Heinz Nixdorf Recall Study

Body mass index (BMI) is influenced by genetic, behavioral and environmental factors, while interactions between genetic and socioeconomic factors have been suggested. Aim of the study was to investigate whether socioeconomic position (SEP) interacts with a BMI-related genetic sum score (GRS_BMI) to affect BMI in a population-based cohort. SEP-related health behaviors and a GRS associated with educational attainment (GRS_Edu) were included in the analysis to explore potential interactions underlying the GRS_BMIxSEP effect. Baseline information on SEP indicators (education, income), BMI, smoking, physical activity, alcohol consumption and genetic risk factors were available for 4,493 participants of the Heinz Nixdorf Recall Study. Interaction analysis was based on linear regression as well as on stratified analyses. In SEP-stratified analyses, the highest genetic effects were observed in the lowest educational group with a 0.24 kg/m² higher BMI (95%CI: 0.16; 0.31) and in the lowest income quartile with a 0.14 kg/m² higher BMI (95%CI: 0.09; 0.18) per additional risk allele. Indication for a GRS_BMIxSEP interaction was observed for education (ß_{GRSbmixeducation} = -0.02 [95%CI:-0.03; -0.01]) and income (ß_{GRSbmixincome} = -0.05 [95%CI: -0.08; -0.02]). When adjusting for interactions with the GRS_Edu and SEP-related health behaviors, effect size estimates of the GRS_BMIxSEP interaction remained virtually unchanged. Results gave indication for an interaction of BMI-related genetic risk factors with SEP indicators, showing substantially stronger genetic effects in low SEP groups. This supports the hypothesis that expression of genetic risks is higher in socioeconomically disadvantaged environments. No indication was observed that the GRS_BMIxSEP interaction was affected by other SEP-related factors included in the analysis.

Adulthood Socioeconomic Position and Type 2 Diabetes Mellitus-A Comparison of Education, Occupation, Income, and Material Deprivation: The Maastricht Study

In an effort to better quantify the impact of adulthood socioeconomic circumstances on prediabetes and type 2 diabetes (T2DM), we set out to examine the relative importance of four adulthood socioeconomic indicators. Using cross-sectional data from The Maastricht Study on 2011 middle-aged older men and women, our findings indicate that low educational level (OR = 1.81, 95% CI = 1.24-2.64), low occupational level (OR = 1.42, 95% CI = 0.98-2.05), and material deprivation (OR = 1.78, 95% CI = 1.33-2.38) were independently associated with T2DM. Low income (OR = 1.28, 95% CI = 0.88-1.87) was the strongest, albeit not significant, SEP (socioeconomic position) correlate of prediabetes. This association confirms SEP as a multifaceted concept and indicates the need to measure SEP accordingly. In order to tackle the social gradient in prediabetes and T2DM, one should, therefore, address multiple SEP indicators and their possible pathways.

Factors related to metabolic parameters in medicated patients with major depressive disorder--a naturalistic study

The aim of this study was to examine the metabolic parameters, including body mass index (BMI), homeostasis model assessment-estimated insulin resistance (HOMA-IR), homeostasis model assessment-estimated pancreatic β-cell function (HOMA-β), and lipid plasma level, in medicated patients with major depressive disorder (MDD) and to assess factors related to metabolic parameters in patients with MDD. 121 patients with MDD and 63 controls were recruited. The Hamilton Depression Rating Scale (HDRS), Wisconsin Card Sorting Test (WCST), Continuous Performance Test (CPT), and Finger-Tapping Test (FTT), were administered. BMI, HOMA-IR, and HOMA-β were calculated as modifiable metabolic parameters. The FTT results and BMI in depressed patients were significantly poorer and lower, respectively, than those of the controls. However, no significant differences were noted between MDD patients and controls included metabolic parameters and other neuropsychological tests. Among depressed patients, higher BMI is significantly related with lower education, no tobacco use, and male. The result demonstrated metabolic parameters could be neutral among medicated patients with MDD, particularly in non-elderly Asian individuals. The deficits of psychomotor speed could be more prominent than other cognitive alterations in patient with MDD.

Does education attenuate the genetic risk of obesity? Evidence from U.K. Twins

More education is associated with a lower body mass index (BMI) and likelihood of being obese. Obesity and BMI also have a strong genetic basis. Given these observations, we investigate whether more education can reduce obesity by attenuating the underlying genetic risk of being obese, through gene-environment (GxE) interactions. We estimate associations between (i) education, (ii) a genetic risk score (GRS) and (iii) GxE interactions between education and the GRS through Ordinary least Squares (OLS) and twins fixed-effect regressions using data on female twins from the TwinsUK database. OLS estimates show that there are significant associations of education and genetics. Female twins with a university education are 14.3 percentage points less likely to be obese compared to twins with less than compulsory education, and a 1 standard deviation increase in the GRS increases the likelihood of being obese by 5.2 percentage points. The GxE interactions are statistically insignificant, suggesting that the marginal association of the GRS with obesity does not differ by educational attainment. When controlling for confounding through twins fixed-effects, we find a smaller role of genetics. The association of the GRS with obesity decreases to 0.040. Associations of educational attainment are substantially reduced and insignificant. GxE interactions also remain insignificant. Overall, we find little evidence of any GxE interactions.

The Interaction of Genetic Predisposition and Socioeconomic Position With Type 2 Diabetes Mellitus: Cross-Sectional and Longitudinal Analyses From the Lifelines Cohort and Biobank Study

OBJECTIVE

A strong genetic predisposition for type 2 diabetes mellitus (T2DM) may aggravate the negative effects of low socioeconomic position (SEP) in the etiology of the disorder. This study aimed to examine cross-sectional and longitudinal associations and interactions of a genetic risk score (GRS) and SEP with T2DM and to investigate whether clinical and behavioral risk factors can explain these associations and interactions.

METHODS

We used data from 13,027 genotyped participants from the Lifelines study. The GRS was based on single-nucleotide polymorphisms genome-wide associated with T2DM and was categorized into tertiles. SEP was measured as educational level. T2DM was based on biological markers, recorded medication use, and self-reports. Cross-sectional and longitudinal associations and interactions between the GRS and SEP on T2DM were examined.

RESULTS

The combination of a high GRS and low SEP had the strongest association with T2DM in cross-sectional (odds ratio = 3.84, 95% confidence interval = 2.28-6.46) and longitudinal analyses (hazard ratio = 2.71, 1.39-5.27), compared with a low GRS and high SEP. Interaction between a high GRS and a low SEP was observed in cross-sectional (relative excess risk due to interaction = 1.85, 0.65-3.05) but not in longitudinal analyses. Clinical and behavioral risk factors mostly explained the observed associations and interactions.

CONCLUSIONS

A high GRS combined with a low SEP provides the highest risk for T2DM. These factors also exacerbated each other's impact cross-sectionally but not longitudinally. Preventive measures should target individual and contextual factors of this high-risk group to reduce the risk of T2DM.

The health benefits of secondary education in adolescents and young adults: An international analysis in 186 low-, middle- and high-income countries from 1990 to 2013

Background

The health benefits of secondary education have been little studied. We undertook country-level longitudinal analyses of the impact of lengthening secondary education on health outcomes amongst 15-24 year olds.

Methods

Exposures: average length of secondary and primary education from 1980 to 2013.

Data/Outcomes: Country level adolescent fertility rate (AFR), HIV prevalence and mortality rate from 1989/90 to 2013 across 186 low-, middle- and high-income countries.

Analysis: Longitudinal mixed effects models, entering secondary and primary education together, adjusted for time varying GDP and country income status. Longitudinal structural marginal models using inverse probability weighting (IPW) to take account of time varying confounding by primary education and GDP. Counterfactual scenarios of no change in secondary education since 1980/1990 were estimated from model coefficients for each outcome.

Findings

Each additional year of secondary education decreased AFR by 8.4% in mixed effects models and 14.6% in IPW models independent of primary education and GDP. Counterfactual analyses showed the proportion of the reduction in adolescent fertility rate over the study period independently attributable to secondary education was 28% in low income countries. Each additional year of secondary education reduced mortality by 16.9% for 15-19 year and 14.8% for 20-24 year old young women and 11.4% for 15-19 year and 8.8% for 20-24 year old young men. Counterfactual scenarios suggested 12% and 23% of the mortality reduction for 15-19 and 20-24 year old young men was attributable to secondary education in low income countries. Each additional year of secondary education was associated with a 24.5% and 43.1% reduction in HIV prevalence amongst young men and women.

Interpretation

The health benefits associated with secondary education were greater than those of primary education and were greatest amongst young women and those from low income countries. Secondary education has the potential to be a social vaccine across many outcomes in low and middle income countries.

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Greater primary education is associated with health benefits.

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Studies suggest that education may have causal effects on health.

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The health benefits of secondary education are greater than for primary education.

Gene-environment interactions between education and body mass: Evidence from the UK and Finland

More education is associated with a lower body mass index (BMI) and likelihood of being overweight. However, since a large proportion of the variation in body mass is due to genetic makeup, it has been hypothesized that education may moderate the genetic risk. We estimate main associations between (i) education, (ii) genetic risk, and (iii) interactions between education and genetic risk on BMI and the probability of being overweight in the UK and Finland. The estimates show that education is negatively associated with BMI and overweightness, and genetic risk is positively associated. However, the interactions between education and genetic risk are small and statistically insignificant.

Education as a moderator of genetic risk for higher body mass index: prospective cohort study from childhood to adulthood

OBJECTIVES

The life-course development of body mass index (BMI) may be driven by interactions between genes and obesity-inducing social environments. We examined whether lower parental or own education accentuates the genetic risk for higher BMI over the life course, and whether diet and physical activity account for the educational differences in genetic associations with BMI.

SUBJECTS/METHODS

The study comprised 2441 participants (1319 women, 3-18 years at baseline) from the prospective, population-based Cardiovascular Risk in Young Finns Study. BMI (kg/m²) trajectories were calculated from 18 to 49 years, using data from six time points spanning 31 years. A polygenic risk score for BMI was calculated as a weighted sum of risk alleles in 97 single-nucleotide polymorphisms. Education was assessed via self-reports, measured prospectively from participants in adulthood and from parents when participants were children. Diet and physical activity were self-reported in adulthood.

RESULTS

Mean BMI increased from 22.6 to 26.6 kg/m² during the follow-up. In growth curve analyses, the genetic risk score was associated with faster BMI increase over time (b=0.02, (95% CI, 0.01-0.02, P<0.001)). The association between the genetic risk score and BMI was more pronounced among those with lower educational level in adulthood (b=-0.12 (95% CI, -0.23-0.01); P=0.036)). No interaction effect was observed between the genetic risk score and parental education (b=0.05 (95% CI, -0.09-0.18; P=0.51)). Diet and physical activity explained little of the interaction effect between the genetic risk score and adulthood education.

CONCLUSIONS

In this prospective study, the association of a risk score of 97 genetic variants with BMI was stronger among those with low compared with high education. This suggests lower education in adulthood accentuates the risk of higher BMI in people at genetic risk.

Decomposing trends in adult body mass index, obesity, and morbid obesity, 1971-2012

Trends in adult obesity have been used to motivate key public health policies in the United States. While these analyses provide important insights into the broad historical contours of the obesity epidemic in the U.S., they shed less light on the proximate mechanisms that have generated these changes and that will ultimately determine the long-term course and pace of change in obesity rates. We used data from the National Health and Nutrition Examination Survey (NHANES), Glenn Firebaugh's linear decomposition technique, and Kitagawa's algebraic decomposition method to decompose change in body mass index (BMI), obesity, and morbid obesity from 1971 through 2012 for adults aged 20+. We partitioned change into that attributable to (1) older, fitter cohorts in the population being replaced by newer, less fit cohorts (intercohort change), and (2) cohort members becoming less fit over time (intracohort change). We found that the rise in mean BMI and rates of obesity and morbid obesity was primarily a consequence of intracohort change driven by variation in the demographic and socioeconomic composition and in the diet of the population over time. Obesity and BMI in the population rose largely because of individual increases in weight status that were broadly distributed across age and cohort groups. Cohort replacement reinforced and amplified intracohort change over the study period, leading to rapid increases in mean BMI and obesity. Because intracohort change has been the central force in the increase in BMI and obesity, successful social, dietary, medical, or policy interventions have the potential to quickly slow or reverse the upward trend in weight status. Our results also imply that policy efforts and health interventions should be broadly targeted at all age groups and birth cohorts because increases in obesity have been widely distributed across all ages and generations.

Stress resilience and subsequent risk of type 2 diabetes in 1.5 million young men

AIMS/HYPOTHESIS

Psychosocial stress in adulthood is associated with a higher risk of type 2 diabetes, possibly mediated by behavioural and physiological factors. However, it is unknown whether low stress resilience earlier in life is related to subsequent development of type 2 diabetes. We examined whether low stress resilience in late adolescence is associated with an increased risk of type 2 diabetes in adulthood.

METHODS

We conducted a national cohort study of all 1,534,425 military conscripts in Sweden during 1969-1997 (97-98% of all 18-year-old men nationwide each year) without prior diagnosis of diabetes, who underwent standardised psychological assessment for stress resilience (on a scale of 1-9) and were followed up for type 2 diabetes identified from outpatient and inpatient diagnoses during 1987-2012 (maximum attained age 62 years).

RESULTS

There were 34,008 men diagnosed with type 2 diabetes in 39.4 million person-years of follow-up. Low stress resilience was associated with an increased risk of developing type 2 diabetes after adjusting for BMI, family history of diabetes, and individual and neighbourhood socioeconomic factors (HR for lowest vs highest quintile: 1.51; 95% CI 1.46, 1.57; p < 0.0001), including a strong linear trend across the full range of stress resilience (p trend < 0.0001). This association did not vary by BMI level, family history of diabetes or socioeconomic factors.

CONCLUSIONS/INTERPRETATION

These findings suggest that low stress resilience may play an important long-term role in aetiological pathways for type 2 diabetes. Further elucidation of the underlying causal factors may help inform more effective preventive interventions across the lifespan.

Current Applications of Genetic Risk Scores to Cardiovascular Outcomes and Subclinical Phenotypes

Genetic risk scores are a useful tool for examining the cumulative predictive ability of genetic variation on cardiovascular disease. Important considerations for creating genetic risk scores include the choice of genetic variants, weighting, and comparability across ethnicities. Genetic risk scores that use information from genome-wide meta-analyses can successfully predict cardiovascular outcomes and subclinical phenotypes, yet there is limited clinical utility of these scores beyond traditional cardiovascular risk factors in many populations. Novel uses of genetic risk scores include evaluating the genetic contribution of specific intermediate traits or risk factors to cardiovascular disease, risk prediction in high-risk populations, gene-by-environment interaction studies, and Mendelian randomization studies. Though questions remain about the ultimate clinical utility of the genetic risk score, further investigation in high-risk populations and new ways to combine genetic risk scores with traditional risk factors may prove to be fruitful.