Gene × dietary pattern interactions in obesity: analysis of up to 68 317 adults of European ancestry

Interactions between Polygenic Risk of Obesity and Dietary Factors on Anthropometric Outcomes: A Systematic Review and Meta-Analysis of Observational Studies

BACKGROUND

Diet is an important determinant of health and may moderate genetic susceptibility to obesity, but meta-analyses of available evidence are lacking.

OBJECTIVES

This study aimed to systematically review and meta-analyze evidence on the moderating effect of diet on genetic susceptibility to obesity, assessed with polygenic risk scores (PRS).

METHODS

A systematic search was conducted using MEDLINE, EMBASE, Web of Science, and the Cochrane Library to retrieve observational studies that examined PRS-diet interactions on obesity-related outcomes. Dietary exposures of interest included diet quality/dietary patterns and consumption of specific food and beverage groups. Random-effects meta-analyses were performed for pooled PRS- healthy eating index (HEI) interaction coefficients on body mass index (BMI) (on the basis of data from 4 cohort studies) and waist circumference (WC) (on the basis of data from 3 cohort studies).

RESULTS

Out of 36 retrieved studies, 78% were conducted among European samples. Twelve out of 21 articles examining dietary indices/patterns, and 16 out of 21 articles examining food/beverage groups observed some significant PRS-diet interactions. However, within many articles, findings are inconsistent when testing different combinations of obesity PRS-dietary factors and outcomes. Nevertheless, higher HEI scores and adherence to plant-based dietary patterns emerged as the more prominent diet quality/patterns that moderated genetic susceptibility to obesity, whereas higher consumption of fruits and vegetables, and lower consumption of fried foods and sugar-sweetened beverages emerged as individual food/beverage moderators. Results from the meta-analysis suggest that a higher HEI attenuates genetic susceptibility on BMI (pooled PRS∗HEI coefficient: -0.08; 95% confidence interval (CI): -0.15, 0.00; P = 0.0392) and WC (-0.37; 95% CI: -0.60, -0.15; P = 0.0013).

CONCLUSIONS

Current observational evidence suggests a moderating role of overall diet quality in polygenic risk of obesity. Future research should aim to identify genetic loci that interact with dietary exposures on anthropometric outcomes and conduct analyses among diverse ethnic groups.

TRIAL REGISTRATION NUMBER

This study was registered at the International Prospective Register of Systematic Reviews as CRD42022312289.

How do lifestyle factors modify the association between genetic predisposition and obesity-related phenotypes? A 4-way decomposition analysis using UK Biobank

BACKGROUND

Obesity and central obesity are multifactorial conditions with genetic and non-genetic (lifestyle and environmental) contributions. There is incomplete understanding of whether lifestyle modifies the translation from respective genetic risks into phenotypic obesity and central obesity, and to what extent genetic predisposition to obesity and central obesity is mediated via lifestyle factors.

METHODS

This is a cross-sectional study of 201,466 (out of approximately 502,000) European participants from UK Biobank and tested for interactions and mediation role of lifestyle factors (diet quality; physical activity levels; total energy intake; sleep duration, and smoking and alcohol intake) between genetic risk for obesity and central obesity. BMI-PRS and WHR-PRS are exposures and obesity and central obesity are outcomes.

RESULTS

Overall, 42.8% of the association between genetic predisposition to obesity and phenotypic obesity was explained by lifestyle: 0.9% by mediation and 41.9% by effect modification. A significant difference between men and women was found in central obesity; the figures were 42.1% (association explained by lifestyle), 1.4% (by mediation), and 40.7% (by modification) in women and 69.6% (association explained by lifestyle), 3.0% (by mediation), and 66.6% (by modification) in men.

CONCLUSIONS

A substantial proportion of the association between genetic predisposition to obesity/central obesity and phenotypic obesity/central obesity was explained by lifestyles. Future studies with repeated measures of obesity and lifestyle would be needed to clarify causation.

Investigation of the interaction between genetic risk score (GRS) and fatty acid quality indices on metabolic syndrome among overweight and obese women

BACKGROUND AND AIM

Metabolic syndrome is one of the major public-health challenges, affecting one-quarter of the world population. Fatty acid quality indices are novel determinants of this disease and their interactions with genetic factors may have an impact on metabolic syndrome risk. Therefore, we aimed to investigate the interaction between genetic risk score (GRS) and fatty acid quality indices with metabolic syndrome (MetS) among overweight and obese women.

METHODS

In the present cross-sectional study, 279 overweight and obese women (18-48 years old) were included. Several anthropometric measurements such as weight, height, body mass index (BMI), waist circumference (WC), and body fat percent (BF%) were measured. Also, systolic and diastolic blood pressure (SBP and DBP) were measured. Biochemical determination was performed for fasting blood glucose (FBS), triglyceride (TG), and high-density lipoprotein (HDL). MetS was determined according to National Cholesterol Education Program (NCEP ATP III) criteria. Dietary intake was evaluated by a validated and reliable 147-item semi-quantitative food frequency questionnaire. Cholesterol-saturated fat index (CSI) and the ratio of omega-6/omega-3 (ω-6/ω-3) essential fatty acids were considered as fat quality indices. The salting-out method was used to extract the total DNA. The unweighted GRS was calculated using the risk alleles of the three single nucleotide polymorphisms. The total average GRS value was 2 and the sum of the risk alleles of the 3 polymorphisms was 6.

RESULT

The results of our analysis showed that after controlling for age, energy intake, BMI, and physical activity, there was a positive interaction between T2 of GRS and T2 of N6/N3 ratio on WC (β = 7.95, 95%CI = 0.83,15.08, P = 0.029), T3 of GRS and T2 of N6/N3 ratio on DBP (β = 5.93, 95%CI= -0.76,12.63, P = 0.083), and FBS (β = 6.47, 95%CI = 0.59,13.53, P = 0.073), T3 of GRS and T3 of N6/N3 ratio on TG (β = 54.42, 95%CI = 1.76,107.08, P = 0.043), and T3 of GRS and T3 of CSI on BF% (β = 3.55, 95%CI= -0.35,7.45, P = 0.075). Also T2 of GRS in the interaction with T3 of CSI leads to an decrease - 8.35 mg/dl in HDL level after adjustment in (β= -8.35, 95%CI= -17.34,0.62, P = 0.068).

CONCLUSION

It seems the interaction of GRS and fatty acid quality indices is positively associated with several components of metabolic syndrome such as WC, TG and BF%. Our findings are of importance to public health, considering the high consumption of foods that are high on fatty acids. Conflicting evidence of many previous studies regarding the effect of fat intake and obesity and cardiovascular diseases could be because of the gene-diet interactions and genetic heterogeneity across various ethnic groups. Hence, the synergism effect of genetic and dietay intakes should be considered in future studies.

Assessment of the impact of a personalised nutrition intervention in impaired glucose regulation over 26 weeks: a randomised controlled trial

Dietary interventions can reduce progression to type 2 diabetes mellitus (T2DM) in people with non-diabetic hyperglycaemia. In this study we aimed to determine the impact of a DNA-personalised nutrition intervention in people with non-diabetic hyperglycaemia over 26 weeks. ASPIRE-DNA was a pilot study. Participants were randomised into three arms to receive either (i) Control arm: standard care (NICE guidelines) (n = 51), (ii) Intervention arm: DNA-personalised dietary advice (n = 50), or (iii) Exploratory arm: DNA-personalised dietary advice via a self-guided app and wearable device (n = 46). The primary outcome was the difference in fasting plasma glucose (FPG) between the Control and Intervention arms after 6 weeks. 180 people were recruited, of whom 148 people were randomised, mean age of 59 years (SD = 11), 69% of whom were female. There was no significant difference in the FPG change between the Control and Intervention arms at 6 weeks (- 0.13 mmol/L (95% CI [- 0.37, 0.11]), p = 0.29), however, we found that a DNA-personalised dietary intervention led to a significant reduction of FPG at 26 weeks in the Intervention arm when compared to standard care (- 0.019 (SD = 0.008), p = 0.01), as did the Exploratory arm (- 0.021 (SD = 0.008), p = 0.006). HbA1c at 26 weeks was significantly reduced in the Intervention arm when compared to standard care (- 0.038 (SD = 0.018), p = 0.04). There was some evidence suggesting prevention of progression to T2DM across the groups that received a DNA-based intervention (p = 0.06). Personalisation of dietary advice based on DNA did not result in glucose changes within the first 6 weeks but was associated with significant reduction of FPG and HbA1c at 26 weeks when compared to standard care. The DNA-based diet was effective regardless of intervention type, though results should be interpreted with caution due to the low sample size. These findings suggest that DNA-based dietary guidance is an effective intervention compared to standard care, but there is still a minimum timeframe of adherence to the intervention before changes in clinical outcomes become apparent.Trial Registration: www.clinicaltrials.gov.uk Ref: NCT03702465.

The Interaction Between Body Mass Index Genetic Risk Score and Dietary Intake on Weight Status: A Systematic Review

Background

The escalating global obesity epidemic and the emergence of personalized medicine strategies point to the pressing need to investigate the interplay between genetic risk scores (GRSs), dietary intake, and their combined impact on weight status. This systematic review synthesizes evidence from diverse studies to elucidate how dietary patterns and individual foods interact with genetic predisposition to obesity.

Methods

Literature searches were conducted in the PubMed, Embase, Science Direct, and Scopus databases until August 2023, following PRISMA guidelines. Out of 575 articles, 15 articles examining the interaction between genetic risk score for body mass index and dietary intake on weight outcomes met the inclusion criteria. All included studies were cross-sectional in design and were assessed for quality using the Newcastle‒Ottawa Scale.

Results

Unhealthy dietary intake exacerbated the genetic predisposition to obesity, evident in studies assessing Western diet, sulfur microbial diet, and individual macronutrients, including saturated fatty acids, sugar-sweetened beverages and fried foods. Conversely, adhering to healthier dietary intake mitigated the genetic predisposition to obesity, as observed in studies involving Alternative Healthy Eating Index, Alternative Mediterranean Diet, Dietary Approach to Stop Hypertension scores, healthy plant-based diets, and specific foods such as fruits, vegetables, and n-3 polyunsaturated fatty acids.

Conclusion

This is the first systematic review to explore the interaction between genetics and dietary intake in shaping obesity outcomes. The findings have implications for tailored interventions; however, more controlled clinical trials with robust designs are needed to be able to recommend personalized nutrition based on nutrition for obesity prevention and management.

Interaction between genetic susceptibility to obesity and food intake on BMI in Finnish school-aged children

Diet modulates the genetic risk of obesity, but the modulation has been rarely studied using genetic risk scores (GRSs) in children. Our objectives were to identify single nucleotide polymorphisms (SNPs) that drive the interaction of specific foods with obesity and combine these into GRSs. Genetic and food frequency data from Finnish Health in Teens study was utilized. In total, 1142 11-year-old subjects were genotyped on the Metabochip array. BMI-GRS with 30 well-known SNPs was computed and the interaction of individual SNPs with food items and their summary dietary scores were examined in relation to age- and sex-specific BMI z-score (BMIz). The whole BMI-GRS interacted with several foods on BMIz. We identified 7-11 SNPs responsible for each interaction and these were combined into food-specific GRS. The most predominant interaction was witnessed for pizza (p < 0.001): the effect on BMIz was b - 0.130 (95% CI - 0.23; - 0.031) in those with low-risk, and 0.153 (95% CI 0.072; 0.234) in high-risk. Corresponding, but weaker interactions were verified for sweets and chocolate, sugary juice drink, and hamburger and hotdog. In total 5 SNPs close to genes NEGR1, SEC16B, TMEM18, GNPDA2, and FTO were shared between these interactions. Our results suggested that children genetically prone to obesity showed a stronger association of unhealthy foods with BMIz than those with lower genetic susceptibility. Shared SNPs of the interactions suggest common differences in metabolic gene-diet interactions, which warrants further investigation.

Identification of a weight loss-associated causal eQTL in MTIF3 and the effects of MTIF3 deficiency on human adipocyte function

Genetic variation at the MTIF3 (Mitochondrial Translational Initiation Factor 3) locus has been robustly associated with obesity in humans, but the functional basis behind this association is not known. Here, we applied luciferase reporter assay to map potential functional variants in the haplotype block tagged by rs1885988 and used CRISPR-Cas9 to edit the potential functional variants to confirm the regulatory effects on MTIF3 expression. We further conducted functional studies on MTIF3-deficient differentiated human white adipocyte cell line (hWAs-iCas9), generated through inducible expression of CRISPR-Cas9 combined with delivery of synthetic MTIF3-targeting guide RNA. We demonstrate that rs67785913-centered DNA fragment (in LD with rs1885988, r² > 0.8) enhances transcription in a luciferase reporter assay, and CRISPR-Cas9-edited rs67785913 CTCT cells show significantly higher MTIF3 expression than rs67785913 CT cells. Perturbed MTIF3 expression led to reduced mitochondrial respiration and endogenous fatty acid oxidation, as well as altered expression of mitochondrial DNA-encoded genes and proteins, and disturbed mitochondrial OXPHOS complex assembly. Furthermore, after glucose restriction, the MTIF3 knockout cells retained more triglycerides than control cells. This study demonstrates an adipocyte function-specific role of MTIF3, which originates in the maintenance of mitochondrial function, providing potential explanations for why MTIF3 genetic variation at rs67785913 is associated with body corpulence and response to weight loss interventions.

Impacts of food consumption on biochemical markers and anthropometric variables of women with metabolic syndrome

BACKGROUND

Metabolic syndrome (MetS) is a group of diseases characterized by insulin resistance. MetS has high prevalence among women, which is impacted by food intake. MetS is related to high level of inflammation; however, the impacts of whole diets on biochemical and anthropometrical markers and the effects on MetS need to be further elucidated. In this case, the objective of this study was to assess the relationship between food intake, biochemical and anthropometrical markers in women with MetS.

METHODS

This is a cross-sectional study, in which 1 hundred and 22 women participated in the assessment of biochemical (glycated hemoglobin, glycaemia, insulin, uric acid, total cholesterol, HDL-c, LDL-c, triglycerides, C-reactive protein) and anthropometrical (body mass, height, waist circumference - WC) variables. Participants also performed blood pressure and 24-hour dietary recall assessments. Out of the 122 participants, 44 (36%, age: 59 ± 11 years) had MetS and were included in the analysis.

RESULTS

The consumption of monounsaturated fats had direct relationship with glycaemia (b = 7.48), whereas the consumption of fibers had inverse relationship with body mass (b = - 0.71) and WC (b = - 0.56).

CONCLUSION

The intake of monounsaturated fats and fiber was related to higher blood sugar levels and lower body mass and WC, respectively. These relationships elucidate and highlight the significance and importance of adequate diet in women with MetS.

Haplotype of ESR1 and PPARD Genes Is Associated with Higher Anthropometric Changes in Han Chinese Obesity by Adjusting Dietary Factors-An 18-Month Follow-Up

The obesity genetic effect may play a major role in obesogenic environment. A combined case-control and an 18-month follow-up were carried out, including a total of 311 controls and 118 obese cases. All participants were aged in the range of 20-55 y/o. The body mass index (BMI) of obese cases and normal controls was in the range of 27.0-34.9 and 18.5-23.9 kg/m², respectively. The rs712221 on Estrogen receptor1 (ESR1) and rs2016520 on Peroxisome proliferator-activated receptor delta (PPARD) showed significant associations with obesity. The TT (odds ratio (OR): 2.42; 95% confidence interval (CI): 1.46-4.01) and TT/TC (OR: 2.80; 95% CI: 1.14-6.85) genotypes on rs712221 and rs2016520 had significantly higher obesity risks, respectively. Moreover, the synergic effect of these two risk SNPs (2-RGH) exhibited an almost geometrical increase in obesity risk (OR: 7.00; 95% CI: 2.23-21.99). Obese individuals with 2-RGH had apparently higher changes in BMI increase, body weight gain and dietary fiber intake but a lower total energy intake within the 18-month follow-up.

In the context of the triple burden of malnutrition: A systematic review of gene-diet interactions and nutritional status

Genetic background interacts with dietary components to modulate nutritional health status. This study aimed to review the evidence for gene-diet interactions in all forms of malnutrition. A comprehensive systematic literature search was conducted through April 2021 to identify observational and intervention studies reporting the effects of gene-diet interactions in over-nutrition, under-nutrition and micronutrient status. Risk of publication bias was assessed using the Quality Criteria Checklist and a tool specifically designed for gene-diet interaction research. 167 studies from 27 populations were included. The majority of studies investigated single nucleotide polymorphisms (SNPs) in overnutrition (n = 158). Diets rich in whole grains, vegetables, fruits and low in total and saturated fats, such as Mediterranean and DASH diets, showed promising effects for reducing obesity risk among individuals who had higher genetic risk scores for obesity, particularly the risk alleles carriers of FTO rs9939609, rs1121980 and rs1421085. Other SNPs in MC4R, PPARG and APOA5 genes were also commonly studied for interaction with diet on overnutrition though findings were inconclusive. Only limited data were found related to undernutrition (n = 1) and micronutrient status (n = 9). The findings on gene-diet interactions in this review highlight the importance of personalized nutrition, and more research on undernutrition and micronutrient status is warranted.

Chronic Stress, Genetic Risk, and Obesity in US Hispanic/Latinos: Results From the Hispanic Community Health Study/Study of Latinos

OBJECTIVE

This study aimed to investigate whether the association of chronic stress with obesity is independent of genetic risk and test whether it varies by the underlying genetic risk.

METHODS

The analysis included data from the Hispanic Community Health Study/Study of Latinos, a community-based study of Hispanic/Latinos living in four US communities (Bronx, NY; Chicago, IL; Miami, FL; San Diego, CA). The sample consisted of 5336 women and 3231 men who attended the Hispanic Community Health Study/Study of Latinos second in-person examination, had measures of obesity, and chronic stress, and were genotyped. Chronic stress burden was assessed by an eight-item scale. An overall polygenic risk score was calculated based on the summary statistics from GIANT and UK BioBank meta-analysis of body mass index (BMI) genome-wide association studies. Mixed-effect models were used to account for genetic relatedness and sampling design, as well as to adjust for potential confounders.

RESULTS

A higher number of chronic stressors were associated with both BMI ( β [log odds] = 0.31 [95% confidence interval = 0.23-0.38]) and obesity ( β [log odds] = 0.10 [95% confidence interval = 0.07-0.13]), after adjustment for covariates and genetic risk. No interactions were found between chronic stress and the genetic risk score for BMI or obesity.

CONCLUSIONS

We did not find evidence for an interaction between chronic stress and polygenic risk score, which was not consistent with other publications that showed greater BMI or obesity in the groups with high stressors and elevated genetic risk.

The association of genetic susceptibility to smoking with cardiovascular disease mortality and the benefits of adhering to a DASH diet: The Singapore Chinese Health Study

BACKGROUND

Understanding the genetic predisposition to cardiovascular disease (CVD) may help to improve clinical intervention strategies. Lifestyle factors, such as diet, may differ among ethnic groups and may, in turn, modify individuals' risks to diseases.

OBJECTIVES

We examined the genetic predisposition to ever smoking in relation to CVD mortality and assessed whether such an association could be modified by dietary intake.

METHODS

A total of 23,760 Chinese adults from the Singapore Chinese Heath Study who were free of cancer and CVD at recruitment (1993-1998) were included in the study. A weighted genetic risk score (wGRS) was calculated to define the genetically determined regular smoking behavior (never or ever). Multivariable-adjusted Cox regression models were used to assess the association between the wGRS and CVD mortality. We also conducted a 1-sample Mendelian randomization analysis for ever smoking and CVD mortality.

RESULTS

Over a mean of 22.6 years of follow-up, 2301 CVD deaths were identified. A genetic predisposition to ever smoking was significantly associated with CVD mortality; the multivariable-adjusted HR of CVD mortality was 1.07 (95% CI: 1.03-1.12), with a per-SD increment in the wGRS. However, the Mendelian randomization analysis did not support a causal relationship between ever smoking and CVD mortality (OR, 1.13; 95% CI: 0.87-1.45). Additionally, the Dietary Approaches to Stop Hypertension (DASH) score significantly modified the association between the smoking wGRS and CVD mortality; the association between a genetic predisposition to smoking and CVD mortality was only observed among individuals with a low DASH score (P-interaction = 0.004).

CONCLUSIONS

A genetic predisposition to smoking was associated with CVD mortality in the Chinese population. In addition, we detected a significant interaction showing higher CVD mortality related to genetically determined smoking among those with lower DASH scores.

Canalization of the Polygenic Risk for Common Diseases and Traits in the UK Biobank Cohort

Since organisms develop and thrive in the face of constant perturbations due to environmental and genetic variation, species may evolve resilient genetic architectures. We sought evidence for this process, known as canalization, through a comparison of the prevalence of phenotypes as a function of the polygenic score (PGS) across environments in the UK Biobank cohort study. Contrasting seven diseases and three categorical phenotypes with respect to 151 exposures in 408,925 people, the deviation between the prevalence-risk curves was observed to increase monotonically with the PGS percentile in one-fifth of the comparisons, suggesting extensive PGS-by-Environment (PGS×E) interaction. After adjustment for the dependency of allelic effect sizes on increased prevalence in the perturbing environment, cases where polygenic influences are greater or lesser than expected are seen to be particularly pervasive for educational attainment, obesity, and metabolic condition type-2 diabetes. Inflammatory bowel disease analysis shows fewer interactions but confirms that smoking and some aspects of diet influence risk. Notably, body mass index has more evidence for decanalization (increased genetic influence at the extremes of polygenic risk), whereas the waist-to-hip ratio shows canalization, reflecting different evolutionary pressures on the architectures of these weight-related traits. An additional 10 % of comparisons showed evidence for an additive shift of prevalence independent of PGS between exposures. These results provide the first widespread evidence for canalization protecting against disease in humans and have implications for personalized medicine as well as understanding the evolution of complex traits. The findings can be explored through an R shiny app at https://canalization-gibsonlab.shinyapps.io/rshiny/.

Mediterranean Diet and Genetic Determinants of Obesity and Metabolic Syndrome in European Children and Adolescents

Childhood obesity and metabolic syndrome (MetS) are multifactorial diseases influenced by genetic and environmental factors. The Mediterranean Diet (MD) seems to modulate the genetic predisposition to obesity or MetS in European adults. The FTO gene has also been shown to have an impact on the MD benefits to avoid obesity or MetS. Since these interaction effects have been scarcely analyzed in European youth, the aim was to describe the gene–MD interplay, analyzing the impact of the genetic factors to reduce the obesity and MetS risk through MD adherence, and the MD impact in the obesity and MetS genetic profile. From the limited evidence on gene–MD interaction studies in European youth, a study showed that the influence of high MD adherence on adiposity and MetS was only observed with a limited number of risk alleles; the gene–MD interplay showed sex-specific differences, being higher in females. Most results analyzed in European adults elucidate that, the relationship between MD adherence and both obesity and MetS risk, could be modulated by obesity genetic variants and vice versa. Further research is needed, to better understand the inter-individual differences in the association between MD and body composition, and the integration of omics and personalized nutrition considering MD.

Specific Dietary Protein Sources Are Associated with Cardiometabolic Risk Factors in the Boston Puerto Rican Health Study

BACKGROUND

Puerto Rican adults residing in the US mainland experience a high prevalence of metabolic syndrome (MetS). A diet containing healthy protein-rich sources may help control risk factors for MetS.

OBJECTIVE

This study aimed to evaluate 2-year longitudinal associations between intake of various protein-rich foods and changes in the six MetS components.

DESIGN

This is a secondary analysis of a longitudinal cohort study using data from the baseline (2004-2007) and 2-year follow-up visits (2006-2011) in the Boston Puerto Rican Health Study.

PARTICIPANTS/SETTING

Participants were self-identified Puerto Ricans, aged 45 to 75 years, residing in Boston, Massachusetts, or the surrounding area (n = 1,126).

MAIN OUTCOME MEASURES

MetS components were fasting glucose, high-density lipoprotein (HDL) cholesterol, triglycerides, systolic and diastolic blood pressures, and waist circumference.

STATISTICAL ANALYSIS

Baseline intake of foods reported in a semiquantitative food frequency questionnaire were expressed as servings/day, and protein-rich foods were categorized as unprocessed white meat, unprocessed red meat, processed meat, milk and yogurt, cheese, fish and seafood, beans, nuts, and eggs. Associations between each continuous protein food group and continuous 2-year change in MetS components were assessed using linear mixed models adjusted for socioeconomic and behavioral factors, and other dietary sources.

RESULTS

The top contributors to total protein intake were unprocessed red meat (13.3%) and unprocessed poultry (13.0%), and the lowest were eggs (2.92%) and nuts (0.91%). Higher intake of processed meats was associated with an increase in waist circumference over 2 years (β = 1.28; standard error [SE] = 0.63), whereas higher intake of fish and seafood was associated with a decrease in waist circumference (β = -3.47; SE = 1.39). Intake of unprocessed poultry was associated with a decrease in triglycerides (β = -24.5; SE = 9.13). No other significant associations were observed between protein sources and 2-year changes in MetS components.

CONCLUSIONS

Consuming less processed meat and more fish and seafood and unprocessed poultry was associated with decreases in waist circumference and triglycerides among US mainland Puerto Ricans. Other dietary protein sources were not related to cardiometabolic health.

Multi-Omic Approaches to Identify Genetic Factors in Metabolic Syndrome

Metabolic syndrome (MetS) is a highly heritable disease and a major public health burden worldwide. MetS diagnosis criteria are met by the simultaneous presence of any three of the following: high triglycerides, low HDL/high LDL cholesterol, insulin resistance, hypertension, and central obesity. These diseases act synergistically in people suffering from MetS and dramatically increase risk of morbidity and mortality due to stroke and cardiovascular disease, as well as certain cancers. Each of these component features is itself a complex disease, as is MetS. As a genetically complex disease, genetic risk factors for MetS are numerous, but not very powerful individually, often requiring specific environmental stressors for the disease to manifest. When taken together, all sequence variants that contribute to MetS disease risk explain only a fraction of the heritable variance, suggesting additional, novel loci have yet to be discovered. In this article, we will give a brief overview on the genetic concepts needed to interpret genome-wide association studies (GWAS) and quantitative trait locus (QTL) data, summarize the state of the field of MetS physiological genomics, and to introduce tools and resources that can be used by the physiologist to integrate genomics into their own research on MetS and any of its component features. There is a wealth of phenotypic and molecular data in animal models and humans that can be leveraged as outlined in this article. Integrating these multi-omic QTL data for complex diseases such as MetS provides a means to unravel the pathways and mechanisms leading to complex disease and promise for novel treatments. © 2022 American Physiological Society. Compr Physiol 12:1-40, 2022.

Interactions between Polygenic Risk Scores, Dietary Pattern, and Menarche Age with the Obesity Risk in a Large Hospital-Based Cohort

Obese Asians are more susceptible to metabolic diseases than obese Caucasians of the same body mass index (BMI). We hypothesized that the genetic variants associated with obesity risk interact with the lifestyles of middle-aged and elderly adults, possibly allowing the development of personalized interventions based on genotype. We aimed to examine this hypothesis in a large city hospital-based cohort in Korea. The participants with cancers, thyroid diseases, chronic kidney disease, or brain-related diseases were excluded. The participants were divided into case and control according to their BMI: ≥25 kg/m2 (case; n = 17,545) and <25 kg/m2 (control; n = 36,283). The genetic variants that affected obesity risk were selected using a genome-wide association study, and the genetic variants that interacted with each other were identified by generalized multifactor dimensionality reduction analysis. The selected genetic variants were confirmed in the Ansan/Ansung cohort, and polygenetic risk scores (PRS)-nutrient interactions for obesity risk were determined. A high BMI was associated with a high-fat mass (odds ratio (OR) = 20.71) and a high skeletal muscle-mass index (OR = 3.38). A high BMI was positively related to metabolic syndrome and its components, including lipid profiles, whereas the initial menstruation age was inversely associated with a high BMI (OR = 0.78). The best model with 5-SNPs included SEC16B_rs543874, DNAJC27_rs713586, BDNF_rs6265, MC4R_rs6567160, and GIPR_rs1444988703. The high PRS with the 5-SNP model was positively associated with an obesity risk of 1.629 (1.475-1.798) after adjusting for the covariates. The 5-SNP model interacted with the initial menstruation age, fried foods, and plant-based diet for BMI risk. The participants with a high PRS also had a higher obesity risk when combined with early menarche, low plant-based diet, and a high fried-food intake than in participants with late menarche, high plant-based diet, and low fried-food intake. In conclusion, people with a high PRS and earlier menarche age are recommended to consume fewer fried foods and a more plant-based diet to decrease obesity risk. This result can be applied to personalized nutrition for preventing obesity.

The interaction between genetic polymorphisms in FTO, MC4R and MTHFR genes and adherence to the Mediterranean Diet in relation to obesity

AIMS

To investigate the potential interaction between genetic background and adherence to the Mediterranean Diet, macronutrient intake and physical activity with regard to obesity in a sample of healthy adults.

DESIGN

Cross-sectional epidemiological study including 392 adults living in the Mediterranean basin. Data including FFQ, IPAQ and sociodemographic questionnaires were collected via face-to-face interviews. Anthropometric measures were performed and saliva swab for DNA extraction. Two MD scores were calculated to assess the adherence of the population to this pattern. Three single nucleotid polymorphisms (SNPs) related to obesity were studied: FTO, MC4R, MTHFR.

FINDINGS

FTO rs9939609 is significantly associated with WHR, and MC4R with all phenotypic traits linked to obesity (BMI, WC and WHR). However, MTHFR polymorphism didn't show any significant correlation with anthropometric parameters. Adherence to the MD and high level of physical activity do not seem to protect against the occurrence of overweight and obesity in genetically predisposed subjects.

CONCLUSION

Classic lifestyle interventions are insufficient in addressing the challenging obesity pandemic. Identifying more genetic variants and understanding their interaction with lifestyle will improve the clinical outcome of these variants for risk prediction and personalized nutrition and medical therapy. Also, the MD should undergo a redefinition adapted to each country on the Mediterranean basin in order to organize public health measures for its comeback.

Impact of dietary and obesity genetic risk scores on weight gain

BACKGROUND

Whether genetic background and/or dietary behaviors influence weight gain in middle-aged subjects is debated.

OBJECTIVE

To assess whether genetic background and/or dietary behaviors are associated with changes in obesity markers (BMI, weight, and waist and hip circumferences) in a Swiss population-based cohort.

METHODS

Cross-sectional and prospective (follow-up of 5.3 y) study. Two obesity genetic risk scores (GRS) based on 31 or 68 single nucleotide polymorphisms were used. Dietary intake was assessed using a semiquantitative FFQ. Three dietary patterns "Meat & fries" (unhealthy), "Fruits & vegetables" (healthy), and "Fatty & sugary" (unhealthy), and 3 dietary scores (2 Mediterranean and the Alternative Healthy Eating Index [AHEI]) were computed.

RESULTS

On cross-sectional analysis (N = 3033, 53.2% females, 58.4 ± 10.6 y), obesity markers were positively associated with unhealthy dietary patterns and GRS, and negatively associated with healthy dietary scores and patterns. On prospective analysis (N = 2542, 54.7% females, age at baseline 58.0 ± 10.4 y), the AHEI and the "Fruits & vegetables" pattern were negatively associated with waist circumference gain: multivariate-adjusted average ± SE 0.96 ± 0.25 compared with 0.11 ± 0.26 cm (P for trend 0.044), and 1.14 ± 0.26 compared with -0.05 ± 0.26 cm (P for trend 0.042) for the first and fourth quartiles of the AHEI and the "Fruits & vegetables" pattern, respectively. Similar inverse associations were obtained for changes in waist >5 cm: multivariate-adjusted OR (95% CI): 0.65 (0.50, 0.85) and 0.67 (0.51, 0.89) for the fourth versus the first quartile of the AHEI and the "Fruits & vegetables" dietary pattern, respectively. No associations were found between GRS and changes in obesity markers, and no significant gene-diet interactions were found.

CONCLUSION

Dietary intake, not GRS, are associated with waist circumference in middle-aged subjects living in Lausanne, Switzerland.

Ancestry specific associations of a genetic risk score, dietary patterns and metabolic syndrome: a longitudinal ARIC study

BACKGROUND

Associations have been observed among genetic variants, dietary patterns, and metabolic syndrome (MetS). A gap in knowledge is whether a genetic risk score (GRS) and dietary patterns interact to increase MetS risk among African Americans. We investigated whether MetS risk was influenced by interaction between a GRS and dietary patterns among Whites and African Americans. A secondary aim examined if molecular genetic clusterings differed by racial ancestry.

METHODS

We used longitudinal data over 4-visits (1987-1998) that included 10,681 participants aged 45-64y at baseline from the Atherosclerosis Risk in Communities study (8451 Whites and 2230 African Americans). We constructed a simple-count GRS as the linear weighted sum of high-risk alleles (0, 1, 2) from cardiovascular disease polymorphisms from the genome-wide association studies catalog associated with MetS risk. Three dietary patterns were determined by factor analysis of food frequency questionnaire data: Western, healthy, and high-fat dairy. MetS was defined according to the 2016 National Cholesterol Education Program Adult Treatment Panel III criteria but used 2017 American Heart Association/American College of Cardiology criteria for elevated blood pressure. Analyses included generalized linear model risk ratios (RR), 95% confidence intervals (CI), and Bonferroni correction for multiple testing.

RESULTS

The Western dietary pattern was associated with higher risk for MetS across increasing GRS tertiles among Whites (p < 0.017). The high-fat dairy pattern was protective against MetS, but its impact was most effective in the lowest GRS tertile in Whites (RR = 0.62; CI: 0.52-0.74) and African Americans (RR = 0.67; CI: 0.49-0.91). Among each racial group within GRS tertiles, the Western dietary pattern was associated with development and cycling of MetS status between visits, and the high-fat dairy pattern with being free from MetS (p < 0.017). The healthy dietary pattern was associated with higher risk of MetS among African Americans which may be explained by higher sucrose intake (p < 0.0001). Fewer genes, but more metabolic pathways for obesity, body fat distribution, and lipid and carbohydrate metabolism were identified in African Americans than Whites. Some polymorphisms were linked to the Western and high-fat dairy patterns.

CONCLUSION

The influence of dietary patterns on MetS risk appears to differ by genetic predisposition and racial ancestry.

Strategies to Understand the Weight-Reduced State: Genetics and Brain Imaging

Most individuals with obesity or overweight have difficulty maintaining weight loss. The weight-reduced state induces changes in many physiological processes that appear to drive weight regain. Here, we review the use of cell biology, genetics, and imaging techniques that are being used to begin understanding why weight regain is the normal response to dieting. As with obesity itself, weight regain has both genetic and environmental drivers. Genetic drivers for "thinness" and "obesity" largely overlap, but there is evidence for specific genetic loci that are different for each of these weight states. There is only limited information regarding the genetics of weight regain. Currently, most genetic loci related to weight point to the central nervous system as the organ responsible for determining the weight set point. Neuroimaging tools have proved useful in studying the contribution of the central nervous system to the weight-reduced state in humans. Neuroimaging technologies fall into three broad categories: functional, connectivity, and structural neuroimaging. Connectivity and structural imaging techniques offer unique opportunities for testing mechanistic hypotheses about changes in brain function or tissue structure in the weight-reduced state.

Variants in Circadian Rhythm Gene Cry1 Interacts with Healthy Dietary Pattern for Serum Leptin Levels: a Cross-sectional Study

Circadian disruption causes obesity and other metabolic disorders. There is no research considering the role of Cryptochromes (Cry) 1 body clock gene and major dietary patterns on serum leptin level and obesity. We aimed to investigate the interaction between Cry1 circadian gene polymorphisms and major dietary patterns on leptin and obesity related measurements. This study was performed on 377 overweight and obese women. Mean age and body mass index (BMI) of study subjects were 36.64 ± 9.02 years and 30.81 ± 3.8 kg/m², respectively. Dietary assessment was done using a validated 147-item food frequency questionnaire. Cry1 rs2287161 were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Generalized linear models were used for interaction analysis. Healthy and unhealthy dietary pattern (HDP and UDP, respectively) were extracted using factor analysis (principal component analysis). Our study revealed a significant higher weight (p = 0.003) and BMI (p = 0.042) in women carrying CC homozygote compared with G allele carriers. Moreover, our findings showed a significant gene-diet interaction between HDP and Cry1 rs2287161 on BMI (p = 0.034) and serum leptin level (p = 0.056) in which, BMI and serum leptin level were lower in subjects with CC genotype than in those with GG genotype while following HDP. This study suggests a significant interaction between Cry1 rs2287161 polymorphisms and HDP on BMI and serum leptin and the lowering effects were apparent among C allele carriers compared to G allele ones. This data highlights the role of dietary pattern in relation of gene and obesity.

Obesity and eating behavior from the perspective of twin and genetic research

Obesity has dramatically increased during the last decades and is currently one of the most serious global health problems. We present a hypothesis that obesity is a neuro-behavioral disease having a strong genetic background mediated largely by eating behavior and is sensitive to the macro-environment; we study this hypothesis from the perspective of genetic research. Genetic family and genome-wide-association studies have shown well that body mass index (BMI, kg/m²) is a highly heritable and polygenic trait. New genetic variation of BMI emerges after early childhood. Candidate genes of BMI notably express in brain tissue, supporting that this new variation is related to behavior. Obesogenic environments at both childhood family and societal levels reinforce the genetic susceptibility to obesity. Genetic factors have a clear influence on macro-nutrient intake and appetite-related eating behavior traits. Results on the gene-by-diet interactions in obesity are mixed, but emerging evidence suggests that eating behavior traits partly mediate the effect of genes on BMI. However, more rigorous prospective study designs controlling for measurement bias are still needed.

Analysis of the Interaction between Polygenic Risk Score and Calorie Intake in Obesity in the Korean Population

INTRODUCTION

Obesity results from an imbalance in the intake and expenditure of calories that leads to lifestyle-related diseases. Although genome-wide association studies (GWAS) have revealed many obesity-related genetic factors, the interactions of these factors and calorie intake remain unknown. This study aimed to investigate interactions between calorie intake and the polygenic risk score (PRS) of BMI.

METHODS

Three cohorts, i.e., from the Korea Association REsource (KARE; n = 8,736), CArdioVAscular Disease Association Study (CAVAS; n = 9,334), and Health EXAminee (HEXA; n = 28,445), were used for this study. BMI-related genetic loci were selected from previous GWAS. Two scores, PRS, and association (a)PRS, were used; the former was determined from 193 single-nucleotide polymorphisms (SNPs) from 5 GWAS datasets, and the latter from 62 SNPs (potentially associated) from 3 Korean cohorts (meta-analysis, p < 0.01).

RESULTS

PRS and aPRS were significantly associated with BMI in all 3 cohorts but did not exhibit a significant interaction with total calorie intake. Similar results were obtained for obesity. PRS and aPRS were significantly associated with obesity but did not show a significant interaction with total calorie intake. We further analyzed the interaction with protein, fat, and carbohydrate intake. The results were similar to those for total calorie intake, with PRS and aPRS found to not be associated with the interaction of any of the 3 nutrition components for either BMI or obesity.

DISCUSSION

The interaction of BMI PRS with calorie intake was investigated in 3 independent Korean cohorts (total n = 35,094) and no interactions were found between PRS and calorie intake for obesity.

Diet Quality and Food Prices Modify Associations between Genetic Susceptibility to Obesity and Adiposity Outcomes

The role of the retail food environment in obesity risk is unclear, which may be due in part to the lack of consideration of individual differences in the responsivity to food cues. This cross-sectional investigation geo-temporally linked the CARTaGENE biobank (including genetic, dietary, lifestyle, and anthropometric data) with in-store retail food environment data to examine interactions between a polygenic risk score (PRS) for obesity and (1) diet quality (n = 6807) and (2) in-store retail food measures (n = 3718). The outcomes included adiposity-related measures and diet quality assessed using the 2010 Canadian-adapted Healthy Eating Index. A vegetable:soft drink ratio was constructed for each retail measure to assess the relative healthfulness of exposures. Generalized linear models adjusted for individual and neighborhood socio-demographic factors were used to evaluate main and interactive effects. Diet quality significantly modified the association between polygenic risk of obesity and body mass index, waist circumference, and body fat percent. A significant interaction was also observed between PRS and frequency of price discount of vegetables in relation to soft drinks on waist circumference. These results replicate previous reports of diet moderating polygenic risk of obesity and suggest that prices of low vs. high-energy density foods are an intervention target to address population obesity rates.

The genetic architecture of the association between eating behaviors and obesity: combining genetic twin modeling and polygenic risk scores

BACKGROUND

Obesity susceptibility genes are highly expressed in the brain suggesting that they might exert their influence on body weight through eating-related behaviors.

OBJECTIVES

To examine whether the genetic susceptibility to obesity is mediated by eating behavior patterns.

METHODS

Participants were 3977 twins (33% monozygotic, 56% females), aged 31-37 y, from wave 5 of the FinnTwin16 study. They self-reported their height and weight, eating behaviors (15 items), diet quality, and self-measured their waist circumference (WC). For 1055 twins with genome-wide data, we constructed a polygenic risk score for BMI (PRSBMI) using almost 1 million single nucleotide polymorphisms. We used principal component analyses to identify eating behavior patterns, twin modeling to decompose correlations into genetic and environmental components, and structural equation modeling to test mediation models between the PRSBMI, eating behavior patterns, and obesity measures.

RESULTS

We identified 4 moderately heritable (h2 = 36-48%) eating behavior patterns labeled "snacking," "infrequent and unhealthy eating," "avoidant eating," and "emotional and external eating." The highest phenotypic correlation with obesity measures was found for the snacking behavior pattern (r = 0.35 for BMI and r = 0.32 for WC; P < 0.001 for both), largely due to genetic factors in common (bivariate h2 > 70%). The snacking behavior pattern partially mediated the association between the PRSBMI and obesity measures (βindirect = 0.06; 95% CI: 0.02, 0.09; P = 0.002 for BMI; and βindirect = 0.05; 95% CI: 0.02, 0.08; P = 0.003 for WC).

CONCLUSIONS

Eating behavior patterns share a common genetic liability with obesity measures and are moderately heritable. Genetic susceptibility to obesity can be partly mediated by an eating pattern characterized by frequent snacking. Obesity prevention efforts might therefore benefit from focusing on eating behavior change, particularly in genetically susceptible individuals.

Canalization and Robustness in Human Genetics and Disease

Canalization refers to the evolution of populations such that the number of individuals who deviate from the optimum trait, or experience disease, is minimized. In the presence of rapid cultural, environmental, or genetic change, the reverse process of decanalization may contribute to observed increases in disease prevalence. This review starts by defining relevant concepts, drawing distinctions between the canalization of populations and robustness of individuals. It then considers evidence pertaining to three continuous traits and six domains of disease. In each case, existing genetic evidence for genotype-by-environment interactions is insufficient to support a strong inference of decanalization, but we argue that the advent of genome-wide polygenic risk assessment now makes an empirical evaluation of the role of canalization in preventing disease possible. Finally, the contributions of both rare and common variants to congenital abnormality and adult onset disease are considered in light of a new kerplunk model of genetic effects.

Obesity and genetics

Genetics is now known to play a substantial role in the predisposition to obesity and may contribute up to 70% risk for the disease. Over a hundred genes and gene variants related to excess weight have been discovered. Yet, genetic obesity risk does not always translate into actual obesity development, suggesting complex interactions between genetic, behavioral, and environmental influences and resulting epigenetic changes. Rare but serious forms of monogenic obesity typically appear in early childhood. Polygenic obesity is most common and demonstrates strong interplay between genes and the obesogenic environment. This review provides an overview of genetic causes of obesity, potential mechanisms of epigenetic changes, and environmental influences that should diminish obesity bias and offer hope for more effective obesity prevention and intervention strategies.

Genetic variants of VDR and CYP2R1 affect BMI independently of serum vitamin D concentrations

BACKGROUND

Vitamin D metabolism and obesity have been linked by several studies, however the reason for this association is unclear. Our objective was to investigate potential correlations between genetic variants in key enzymes of vitamin D metabolism and the body mass index on a representative and random sample of Hungarian adults.

METHODS

Altogether 462 severely vitamin D deficient individuals were studied at the end of winter in order to decrease environmental and maximize any relevant genetic effect. Furthermore, participants with lifestyle factors known to affect vitamin D homeostasis were also excluded. We selected 23 target SNPs in five genes that encode key proteins of vitamin D metabolism (NADSYN1, GC, CYP24A1, CYP2R1, VDR).

RESULTS

Variants in 2 genetic polymorphisms; rs2853564 (VDR) and rs11023374 (CYP2R1) showed a significant association with participants' BMI. These associations survived further adjustment for total-, free-, or bioactive-25(OH) vitamin D levels, although the variance explained by these 2 SNPS in BMI heterogeneity was only 3.2%.

CONCLUSION

Our results show two novel examples of the relationship between genetics of vitamin D and BMI, highlighting the potential role of vitamin D hormone in the physiology of obesity.

Objectives, design and main findings until 2020 from the Rotterdam Study

The Rotterdam Study is an ongoing prospective cohort study that started in 1990 in the city of Rotterdam, The Netherlands. The study aims to unravel etiology, preclinical course, natural history and potential targets for intervention for chronic diseases in mid-life and late-life. The study focuses on cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, otolaryngological, locomotor, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. Since 2016, the cohort is being expanded by persons aged 40 years and over. The findings of the Rotterdam Study have been presented in over 1700 research articles and reports. This article provides an update on the rationale and design of the study. It also presents a summary of the major findings from the preceding 3 years and outlines developments for the coming period.

Nutritional genomics, inflammation and obesity

The Human Genome Project has significantly broadened our understanding of the molecular aspects regulating the homeostasis and the pathophysiology of different clinical conditions. Consequently, the field of nutrition has been strongly influenced by such improvements in knowledge - especially for determining how nutrients act at the molecular level in different conditions, such as obesity, type 2 diabetes, cardiovascular disease, and cancer. In this manner, characterizing how the genome influences the diet and vice-versa provides insights about the molecular mechanisms involved in chronic inflammation-related diseases. Therefore, the present review aims to discuss the potential application of Nutritional Genomics to modulate obesity-related inflammatory responses. Arch Endocrinol Metab. 2020;64(3):205-22.

Interaction of polymorphisms in APOA4-APOA5-ZPR1-BUD13 gene cluster and sleep duration on 5-year lipid changes in middle aged and older Chinese

STUDY OBJECTIVES

Lipid profiles are influenced by both genetic and environmental factors. Genetic variants in the APOA4-APOA5-ZPR1-BUD13 gene cluster and aberrant sleep duration were independently identified to be associated with lipids in previous studies. We aimed to investigate whether sleep duration modified the genetic associations with longitudinal lipids changes.

METHODS

Four single nucleotide polymorphisms (SNPs), rs17119975, rs651821, rs7396835, and rs964184 in the APOA4-APOA5-ZPR1-BUD13 gene cluster were genotyped among 8648 apparently healthy subjects from the Dongfeng-Tongji (DFTJ) cohort. Information on sleep duration was obtained by questionnaires. Changes in total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), were evaluated from baseline to 5-year follow-up.

RESULTS

After multivariate adjustments, we found that rs651821 and weighted genetic risk score (GRS) were significantly associated with increased triglyceride, and the genetic association with triglyceride change consistently strengthened across sleep duration categories. The differences in triglyceride changes per increment of risk allele for rs651821 were 0.028 (SE = 0.017, p = 0.112), 0.051 (SE = 0.009, p < 0.001), and 0.064 (SE = 0.016, p < 0.001) in individuals with sleep duration ≤7, >7-<9, and ≥9 h, respectively (p interaction = 0.031). The GRS also showed a significant interaction with sleep duration categories for triglyceride change (p interaction = 0.010). In addition, all of the four SNPs and GRS were inversely related to HDL-c changes.

CONCLUSIONS

Longer sleep duration might exacerbate the adverse effects of SNPs in APOA4-APOA5-ZPR1-BUD13 gene cluster on 5-year triglyceride changes.

Hemoglobin A1c Levels Modify Associations between Dietary Acid Load and Breast Cancer Recurrence

BACKGROUND

Metabolic acidosis promotes cancer metastasis. No prospective studies have examined the association between dietary acid load and breast cancer recurrence among breast cancer survivors, who are susceptible to metabolic acidosis. Hyperglycemia promotes cancer progression and acid formation; however, researchers have not examined whether hyperglycemia can modify the association between dietary acid load and breast cancer recurrence.

METHODS

We studied 3081 early-stage breast cancer survivors enrolled in the Women's Healthy Eating and Living study who provided dietary information through 24-h recalls at baseline and during follow-up and had measurements of hemoglobin A1c (HbA1c) at baseline. We assessed dietary acid load using two common dietary acid load scores, potential renal acid load (PRAL) score and net endogenous acid production (NEAP) score.

RESULTS

After an average of 7.3 years of follow-up, dietary acid load was positively associated with recurrence when baseline HbA1c levels were ≥ 5.6% (median level) and ≥5.7% (pre-diabetic cut-point). In the stratum with HbA1c ≥ 5.6%, comparing the highest to the lowest quartile of dietary acid load, the multivariable-adjusted hazard ratio was 2.15 (95% confidence interval [CI] 1.34-3.48) for PRAL and was 2.31 (95% CI 1.42-3.74) for NEAP. No associations were observed in the stratum with HbA1c levels were <5.6%. P-values for interactions were 0.01 for PRAL and 0.05 for NEAP.

CONCLUSIONS

Our study demonstrated for the first time that even at or above normal to high HbA1c levels, dietary acid load was associated with increased risk of breast cancer recurrence among breast cancer survivors.

IMPACTS

Our study provides strong evidence for developing specific dietary acid load guidelines based on HbA1c levels.

Gene-Environment Interactions on Body Fat Distribution

The prevalence of obesity has been increasing markedly in the U.S. and worldwide in the past decades; and notably, the obese populations are signified by not only the overall elevated adiposity but also particularly harmful accumulation of body fat in the central region of the body, namely, abdominal obesity. The profound shift from “traditional” to “obesogenic” environments, principally featured by the abundance of palatable, energy-dense diet, reduced physical activity, and prolonged sedentary time, promotes the obesity epidemics and detrimental body fat distribution. Recent advances in genomics studies shed light on the genetic basis of obesity and body fat distribution. In addition, growing evidence from investigations in large cohorts and clinical trials has lent support to interactions between genetic variations and environmental factors, e.g., diet and lifestyle factors, in relation to obesity and body fat distribution. This review summarizes the recent discoveries from observational studies and randomized clinical trials on the gene–environment interactions on obesity and body fat distribution.

Genetic predictors of weight loss in overweight and obese subjects

The aim of our study was to investigate a large cohort of overweight subjects consuming a homogeneous diet to identify the genetic factors associated with weight loss that could be used as predictive markers in weight loss interventions. We retrospectively recruited subjects (N = 788) aged over 18 years with a Body Mass Index (BMI) between 25 and 40 kg/m² who were treated at our lipid unit for at least one year from 2008 to 2016, and we also recruited a control group (168 patients) with normal BMIs. All participants received counselling from a nutritionist that included healthy diet and physical activity recommendations. We genotyped 25 single nucleotide variants (SNVs) in 25 genes that were previously associated with obesity and calculated genetic scores that were derived from 25 SNVs. The risk allele in CADM2 showed a higher frequency in overweight and obese subjects than in controls (p = 0.007). The mean follow-up duration was 5.58 ± 2.68 years. Subjects with lower genetic scores showed greater weight loss during the follow-up period. The genetic score was the variable that best explained the variations in weight from the baseline. The genetic score explained 2.4% of weight change variance at one year and 1.6% of weight change variance at the end of the follow-up period after adjusting for baseline weight, sex, age and years of follow-up.

Obesity, genomic ancestry, and socioeconomic variables in Latin American mestizos

OBJECTIVES

This article aims to assess the contribution of genomic ancestry and socioeconomic status to obesity in a sample of admixed Latin Americans.

METHODS

The study comprised 6776 adult volunteers from Brazil, Chile, Colombia, Mexico, and Peru. Each volunteer completed a questionnaire about socioeconomic variables. Anthropometric variables such as weight, height, waist, and hip circumference were measured to calculate body indices: body mass index, waist-to-hip ratio and waist-to-height ratio (WHtR). Genetic data were extracted from blood samples, and ancestry was estimated using chip genotypes. Multiple linear regression was used to evaluate the relationship between the indices and ancestry, educational level, and economic well-being. The body indices were dichotomized to obesity indices by using appropriate thresholds. Odds ratios were calculated for each obesity index.

RESULTS

The sample showed high percentages of obesity by all measurements. However, indices did not overlap consistently when classifying obesity. WHtR resulted in the highest prevalence of obesity. Overall, women with low education level and men with high economic wellness were more likely to be obese. American ancestry was statistically associated with obesity indices, although to a lesser extent than socioeconomic variables.

CONCLUSIONS

The proportion of obesity was heavily dependent on the index and the population. Genomic ancestry has a significant influence on the anthropometric measurements, especially on central adiposity. As a whole, we detected a large interpopulation variation that suggests that better approaches to overweight and obesity phenotypes are needed in order to obtain more precise reference values.

EDAR, LYPLAL1, PRDM16, PAX3, DKK1, TNFSF12, CACNA2D3, and SUPT3H gene variants influence facial morphology in a Eurasian population

In human society, the facial surface is visible and recognizable based on the facial shape variation which represents a set of highly polygenic and correlated complex traits. Understanding the genetic basis underlying facial shape traits has important implications in population genetics, developmental biology, and forensic science. A number of single nucleotide polymorphisms (SNPs) are associated with human facial shape variation, mostly in European populations. To bridge the gap between European and Asian populations in term of the genetic basis of facial shape variation, we examined the effect of these SNPs in a European-Asian admixed Eurasian population which included a total of 612 individuals. The coordinates of 17 facial landmarks were derived from high resolution 3dMD facial images, and 136 Euclidean distances between all pairs of landmarks were quantitatively derived. DNA samples were genotyped using the Illumina Infinium Global Screening Array and imputed using the 1000 Genomes reference panel. Genetic association between 125 previously reported facial shape-associated SNPs and 136 facial shape phenotypes was tested using linear regression. As a result, a total of eight SNPs from different loci demonstrated significant association with one or more facial shape traits after adjusting for multiple testing (significance threshold p < 1.28 × 10-3), together explaining up to 6.47% of sex-, age-, and BMI-adjusted facial phenotype variance. These included EDAR rs3827760, LYPLAL1 rs5781117, PRDM16 rs4648379, PAX3 rs7559271, DKK1 rs1194708, TNFSF12 rs80067372, CACNA2D3 rs56063440, and SUPT3H rs227833. Notably, the EDAR rs3827760 and LYPLAL1 rs5781117 SNPs displayed significant association with eight and seven facial phenotypes, respectively (2.39 × 10-5 < p < 1.28 × 10-3). The majority of these SNPs showed a distinct allele frequency between European and East Asian reference panels from the 1000 Genomes Project. These results showed the details of above eight genes influence facial shape variation in a Eurasian population.

Human genes influence the interaction between Streptococcus mutans and host caries susceptibility: a genome-wide association study in children with primary dentition

Streptococcus mutans is a well-known cause of dental caries, due to its acidogenicity, aciduricity, and ability to synthesize exopolysaccharides in dental plaques. Intriguingly, not all children who carry S. mutans manifest caries, even with similar characteristics in oral hygiene, diet, and other environmental factors. This phenomenon suggests that host susceptibility potentially plays a role in the development of dental caries; however, the association between host genetics, S. mutans, and dental caries remains unclear. Therefore, this study examined the influence of host gene-by-S. mutans interaction on dental caries. Genome-wide association analyses were conducted in 709 US children (<13 years old), using the dbGap database acquired from the center for oral health research in appalachia (COHRA) and the Iowa Head Start programmes (GEIRS). A generalized estimating equation was used to examine the gene-by-S. mutans interaction effects on the outcomes (decayed and missing/filled primary teeth due to caries). Sequentially, the COHRA and GEIRS data were used to identify potential interactions and replicate the findings. Three loci at the genes interleukin 32 (IL32), galactokinase 2 (GALK2), and CUGBP, Elav-like family member 4 (CELF4) were linked to S. mutans carriage, and there was a severity of caries at a suggestive significance level among COHRA children (P < 9 × 10-5), and at a nominal significance level among GEIRS children (P = 0.047-0.001). The genetic risk score that combined the three loci also significantly interacted with S. mutans (P < 0.000 1). Functional analyses indicated that the identified genes are involved in the host immune response, galactose carbohydrate metabolism, and food-rewarding system, which could potentially be used to identify children at high risk for caries and to develop personalized caries prevention strategies.

Impact of Genes and Environment on Obesity and Cardiovascular Disease

Obesity and abdominal obesity have been closely related to cardiovascular outcomes, and recent evidence has indicated that environmental and genetic factors act in concert in determining the risks of these conditions. Improving adherence to healthy lifestyle habits and healthy dietary patterns can at least partly counteract genetic variations related to risks of obesity and cardiovascular disease (CVD). Other factors, such as epigenetic alterations, may also modulate a relationship between genetic susceptibility and these disorders. In this review, we highlight data from recent studies on gene and environmental risk factors for obesity and CVD, and describe how these findings might inform understanding of the complex roles of interactions between genes and environmental factors in the development of obesity and CVD.

Diet quality and genetic association with body mass index: results from 3 observational studies

Background

It is unknown whether dietary quality modifies genetic association with body mass index (BMI).

Objective

This study examined whether dietary quality modifies genetic association with BMI.

Design

We calculated 3 diet quality scores including the Alternative Healthy Eating Index 2010 (AHEI-2010), the Alternative Mediterranean Diet score (AMED), and the Dietary Approach to Stop Hypertension (DASH) diet score. We examined the interactions of a genetic risk score (GRS) based on 97 BMI-associated variants with the 3 diet quality scores on BMI in 30,904 participants from 3 large cohorts.

Results

We found significant interactions between total GRS and all 3 diet scores on BMI assessed after 2-3 y, with an attenuated genetic effect observed in individuals with healthier diets (AHEI: P-interaction = 0.003; AMED: P = 0.001; DASH: P = 0.004). For example, the difference in BMI (kg/m2) per 10-unit increment of the GRS was smaller among participants in the highest tertile of AHEI score compared with those in the lowest tertile (0.84; 95% CI: 0.72, 0.96 compared with 1.14; 95% CI: 0.99, 1.29). Results were consistent across the 3 cohorts with no significant heterogeneity. The interactions with diet scores on BMI appeared more significant for central nervous system GRSs (P < 0.01 for 3 diet scores) than for non-central nervous system GRSs (P > 0.05 for 3 diet scores).

Conclusions

A higher diet quality attenuated genetic predisposition to obesity. These findings underscore the importance of maintaining a healthful diet for the prevention of obesity, particularly for those individuals with a strong genetic predisposition to obesity. This trial was registered with the Clinical Trial Registry as NCT03577639.

Novel minor HLA DR associated antigens in type 1 diabetes

Type 1 diabetes is an autoimmune disease leading to insulin deficiency. Autoantibodies to beta cell proteins are already present in the asymptomatic phase of type 1 diabetes. Recent findings have suggested a number of additional minor autoantigens in patients with type 1 diabetes. We have established luciferase immunoprecipitation systems (LIPS) for anti-MTIF3, anti-PPIL2, anti-NUP50 and anti-MLH1 and analyzed samples from 500 patients with type 1 diabetes at onset of clinical disease and 200 healthy individuals who had a family history of type 1 diabetes but no evidence of beta cell autoantibodies. We show significantly higher frequencies of anti-MTIF3, anti-PPIL2 and anti-MLH1 in recent onset type 1 diabetes patients in comparison to controls. In addition, antibodies to NUP50 were associated with HLA-DRB1*03 and antibodies to MLH1 were associated with HLA-DRB1*04 genotypes.

Nutritional Genomics of Cardiovascular Disease

PURPOSE

Cardiovascular disease (CVD) is the leading cause of death in the United States and globally. There is significant evidence implicating genetic and dietary factors in the development and progression of CVD and its risk factors. Nutritional genomics is a comparatively new field of science that focuses on the relationship of individual genetic variation with response to nutrition. The purpose of this review is to summarize recent progress, in the field of nutritional genomics as it relates to cardiovascular disease.

RECENT FINDINGS

Evidence from recent studies has shown significant effects of gene-diet interactions on CVD biomarkers and the development and progression of CVD. The cardiovascular effects of gene-nutrient interactions with respect to macronutrients and genes such as FTO, ACE, PPARs, TCF7L2, BDNF, MC4R, APOAs, FADS, etc. have shown consistent results across age groups and populations whereas gene-nutrient interaction effects of other genes have only been limited to specific ages, genders or populations and need to validated and confirmed.

SUMMARY

The identification of individual genetic variation influencing diet-related CVD risk is important and may inform future nutritional intervention studies. Although there is ample scientific evidence indicating that the genetic susceptibility to CVD can be modified by diet, we are still not at a stage where this information is easily translated into dietary plans. Thus, there is a need for better approaches to achieve precision in dietary data collection and streamline computational approaches for meaningful and effective nutritional interventions.

Nutritional Genomics and Direct-to-Consumer Genetic Testing: An Overview

The increasing prevalence in polygenic diseases, such as obesity, cardiovascular disease, and type 2 diabetes, observed over the past few decades is more likely linked to a rapid transition in lifestyle rather than to changes in the sequence of the nuclear genome. In the new era of precision medicine, nutritional genomics holds the promise to be translated into tailored nutritional strategies to prevent and manage polygenic diseases more effectively. Nutritional genomics aims to prevent, treat, and manage polygenic diseases through targeted therapies formulated from individuals' genetic makeup and dietary intake. Direct-to-consumer genetic testing (DTC-GT) has become commercially available to equip individuals with information on their genetic vulnerability to different diseases. This information may potentially prompt behavioral changes against adverse factors. However, scientific evidence behind the clinical recommendations is a matter of continuous debate, and behavioral modifications after disclosing genetic information remain inconclusive. In this review, we provide an overview of nutritional genomics and related nutritional DTC-GT services and discuss whether available data are sufficient to be translated into clinical recommendations and public health initiatives. Overall, the scientific evidence supporting the dissemination of genomic information for nutrigenomic purposes remains sparse. Therefore, additional knowledge needs to be generated, particularly for polygenic traits.

Genetics of obesity: what genetic association studies have taught us about the biology of obesity and its complications

Genome-wide association studies (GWAS) for BMI, waist-to-hip ratio, and other adiposity traits have identified more than 300 single-nucleotide polymorphisms (SNPs). Although there is reason to hope that these discoveries will eventually lead to new preventive and therapeutic agents for obesity, this will take time because such developments require detailed mechanistic understanding of how an SNP influences phenotype (and this information is largely unavailable). Fortunately, absence of functional information has not prevented GWAS findings from providing insights into the biology of obesity. Genes near loci regulating total body mass are enriched for expression in the CNS, whereas genes for fat distribution are enriched in adipose tissue itself. Gene by environment and lifestyle interaction analyses have revealed that our increasingly obesogenic environment might be amplifying genetic risk for obesity, yet those at highest risk could mitigate this risk by increasing physical activity and possibly by avoiding specific dietary components. GWAS findings have also been used in mendelian randomisation analyses probing the causal association between obesity and its many putative complications. In supporting a causal association of obesity with diabetes, coronary heart disease, specific cancers, and other conditions, these analyses have clinical relevance in identifying which outcomes could be preventable through weight loss interventions.