Association between urinary iodine excretion, genetic disposition and fluid intelligence in children, adolescents and young adults: the DONALD study.

PURPOSE: Iodine deficiency increases the risk of cognitive impairment and delayed physical development in children. It is also associated with cognitive impairment in adults. Cognitive abilities are among the most inheritable behavioural traits. However, little is known about the consequences of insufficient postnatal iodine intake and whether the individual genetic disposition modifies the association between iodine intake and fluid intelligence in children and young adults. METHODS: The cultural fair intelligence test was used to assess fluid intelligence in the participants of the DONALD study (n = 238; mean age, 16.5 [SD = 7.7] years). Urinary iodine excretion, a surrogate iodine intake marker, was measured in 24-h urine. Individual genetic disposition (n = 162) was assessed using a polygenic score, associated with general cognitive function. Linear regression analyses were conducted to determine whether Urinary iodine excretion was associated with fluid intelligence and whether this association was modified by individual genetic disposition. RESULTS: Urinary iodine excretion above the age-specific estimated average requirement was associated with a five-point higher fluid intelligence score than that below the estimated average requirement (P = 0.02). The polygenic score was positively associated with the fluid intelligence score (ß = 2.3; P = 0.03). Participants with a higher polygenic score had a higher fluid intelligence score. CONCLUSION: Urinary iodine excretion above the estimated average requirement in childhood and adolescence is beneficial for fluid intelligence. In adults, fluid intelligence was positively associated with a polygenic score for general cognitive function. No evidence showed that the individual genetic disposition modifies the association between Urinary iodine excretion and fluid intelligence.

A healthy lifestyle during adolescence was inversely associated with fatty liver indices in early adulthood: findings from the DONALD cohort study.

A healthy lifestyle during adolescence is associated with insulin sensitivity or liver enzyme levels and thus might contribute to the prevention of non-alcoholic fatty liver disease (NAFLD). Therefore, we examined the association between adherence to a hypothesis-based lifestyle score including dietary intake, physical activity, sedentary behaviour, sleep duration and BMI in adolescence and fatty liver indices in early adulthood. Overall, 240 participants of the DOrtmund Nutritional and Anthropometric Longitudinally Designed study completed repeated measurements of lifestyle score factors during adolescence (females: 8·5-15·5 years, males: 9·5-16·5 years). Multivariable linear regression models were used to investigate the association between adolescent lifestyle scores and NAFLD risk (hepatic steatosis index (HSI) and fatty liver index (FLI)) in early adulthood (18-30 years). Participants visited the study centre 4·9 times during adolescence and achieved on average 2·8 (min: 0·6, max: 5) out of five lifestyle score points. Inverse associations were observed between the lifestyle score and fatty liver indices (HSI: ß=-5·8 % (95 % CI -8·3, -3·1), P < 0·0001, FLI: ß=-32·4 % (95 % CI -42·9, -20·0), P < 0·0001) in the overall study population. Sex-stratified analysis confirmed these results in men, while inverse but non-significant associations were observed in women (P > 0·05). A higher lifestyle score was associated with lower HSI and FLI values, suggesting that a healthy lifestyle during adolescence might contribute to NAFLD prevention, predominantly in men. Our findings on repeatedly measured lifestyle scores in adolescents and their association with NAFLD risk in early adulthood warrant confirmation in larger study populations.

Analysis of associations between dietary patterns, genetic disposition, and cognitive function in data from UK Biobank.

PURPOSE: Research suggests that diet influences cognitive function and the risk for neurodegenerative disease. The present study aimed to determine whether a recently developed diet score, based on recommendations for dietary priorities for cardio metabolic health, was associated with fluid intelligence, and whether these associations were modified by individual genetic disposition. METHODS: This research has been conducted using the UK Biobank Resource. Analyses were performed using self-report data on diet and the results for the verbal-numerical reasoning test of fluid intelligence of 104,895 individuals (46% male: mean age at recruitment 57.1 years (range 40-70)). For each participant, a diet score and a polygenic score (PGS) were constructed, which evaluated predefined cut-offs for the intake of fruit, vegetables, fish, processed meat, unprocessed meat, whole grain, and refined grain, and ranged from 0 (unfavorable) to 7 (favorable). To investigate whether the diet score was associated with fluid intelligence, and whether the association was modified by PGS, linear regression analyses were performed. RESULTS: The average diet score was 3.9 (SD 1.4). After adjustment for selected confounders, a positive association was found between baseline fluid intelligence and PGS (P < 0.001). No association was found between baseline fluid intelligence and diet score (P = 0.601), even after stratification for PGS, or in participants with longitudinal data available (n = 9,482). CONCLUSION: In this middle-aged cohort, no evidence was found for an association between the investigated diet score and either baseline or longitudinal fluid intelligence. However, as in previous reports, fluid intelligence was strongly associated with a PGS for general cognitive function.

A lifestyle score in childhood and adolescence was positively associated with subsequently measured fluid intelligence in the DONALD cohort study.

PURPOSE: Lifestyle scores which combine single factors such as diet, activity, or sleep duration showed associations with cognitive decline in adults. However, the role of a favourable lifestyle in younger age and the build-up of cognitive reserve is less clear, which is why we investigated longitudinal associations between a lifestyle score in childhood and adolescence and fluid intelligence obtained on average 6 years later. METHODS: In the DONALD cohort, a lifestyle score of 0 to 4 points including healthy diet and duration of moderate-to-vigorous physical activity, sedentary behaviour and sleep was repeatedly assessed in participants aged 5 and 19 years. Data on fluid intelligence were assessed via a German version of the culture fair intelligence test (CFT), using CFT 1-R in children 8.5 years of age or younger (n = 62) or CFT 20-R in participants older than 8.5 years (n = 192). Multivariable linear regression models were used to investigate prospective associations between the lifestyle score and the fluid intelligence score. RESULTS: Mean lifestyle score of all participants was 2.2 (0.7-4) points. A one-point increase in the lifestyle score was associated with a higher fluid intelligence score (4.8 points [0.3-7.3], p = 0.0343) for participants completing the CFT 20-R. Furthermore, each additional hour of sedentary behaviour was associated with a lower fluid intelligence score (- 3.0 points [- 5.7 to - 0.3], p = 0.0313). For younger participants (CFT 1-R), no association was found in any analysis (p > 0.05). CONCLUSION: A healthy lifestyle was positively associated with fluid intelligence, whereby sedentary behaviour itself seemed to play a prominent role.

Associations of Adherence to a Dietary Index Based on the EAT-Lancet Reference Diet with Nutritional, Anthropometric, and Ecological Sustainability Parameters: Results from the German DONALD Cohort Study.

BACKGROUND: Validation of the EAT-Lancet reference diet (ELR-diet), recently proposed by the EAT-Lancet Commission, within the context of real-life studies is necessary to elucidate its feasibility, nutritional value, sustainability, and health effects. OBJECTIVES: We aimed to develop a dietary index (DI) score to measure adherence to the ELR-diet. We further aimed to study the association between the DI score and 1) nutritional characteristics, 2) indicators of ecological sustainability, and 3) anthropometric markers and biomarkers for cardiometabolic health. METHODS: A DI score was constructed by comparing the categories defined by the ELR-diet with the dietary data of 2-5 sets of 3-d weighed dietary records from DONALD (Dortmund Nutritional and Anthropometric Longitudinal Designed) study participants (n = 298; ≥15 y of age). Prospective associations between the DI score and risk markers (anthropometric and cardiometabolic) in young adulthood (≥18 y old) were investigated using multivariate linear regression. RESULTS: Adherence to the DI score components was considerable (majority > 50%), but varied within the population (2%-100%). The highest tertile of the DI score was inversely associated with the intake of protein (tertile 3 compared with tertile 1: 13.5 compared with 14.5 energy %), added sugars (10.5 compared with 12.4 energy %), and cholesterol (100 compared with 116 mg/1000 kcal), but positively associated with fiber intake (10.0 compared with 8.82 g/1000 kcal) (all P < 0.05). The DI score was inversely associated with greenhouse-gas emissions (tertile 1 compared with tertile 3: 6.48 compared with 5.85 kg of carbon dioxide equivalents/2500 kcal; P < 0.001) and land use (8.24 compared with 7.16 m2 × y/2500 kcal; P < 0.001). Inverse associations between the DI score and anthropometric markers during young adulthood were observed (e.g., BMI: tertile 1 compared with tertile 3: 22.9 compared with 21.9 kg/m2; P = 0.03) (all P < 0.05). No associations between the DI score and cardiometabolic risk markers were found (all P ≥ 0.05). CONCLUSIONS: Adherence to the ELR-diet was associated with favorable nutritional characteristics and reduced environmental impact. Adherence to the DI score in adolescence was also beneficial with respect to anthropometric markers in early adulthood, although not for further cardiometabolic risk markers.

A lifestyle pattern during adolescence is associated with cardiovascular risk markers in young adults: results from the DONALD cohort study.

Lifestyle score approaches combining individual lifestyle factors, e.g. favourable diet, physical activity or normal body weight, showed inverse associations with cardiovascular disease (CVD) risk. However, research mainly focussed on adult behaviour and is scarce for vulnerable time windows for adult health like adolescence. We investigated associations between an adolescent lifestyle score and CVD risk markers in young adulthood. Overall, we analysed 270 participants of the open DONALD cohort study with 1-6 complete measurements of five lifestyle factors (healthy diet, moderate-to-vigorous physical activity, sedentary behaviour, sleep duration and BMI standard deviation score) during adolescence (females: 8⋅5-15⋅5 years and males: 9⋅5-16⋅5 years). Multivariable linear regression models were used to investigate the prospective association between the adolescent lifestyle score (0-5 points) and CVD risk markers in young adulthood (18-30 years). On average, participants obtained a mean adolescent lifestyle score of 2⋅9 (0-5) points. Inverse associations between the adolescent lifestyle score and waist circumference, waist-to-height ratio and percentage of body fat were observed (4⋅1, 4⋅1 and 9⋅2 % decrease per 1 point increase in adolescent lifestyle score, respectively, P < 0⋅05). For the remaining CVD risk markers (glucose, blood lipids, blood pressure and a proinflammatory score), no associations were observed. A healthy adolescent lifestyle is particularly associated with CVD risk-related favourable anthropometric markers in adulthood. A more comprehensive understanding of lifestyle patterns in the life course might enable earlier, targeted preventive measures to assist vulnerable groups in prevention of chronic diseases.

Advances in dietary pattern analysis in nutritional epidemiology.

BACKGROUND AND PURPOSE: It used to be a common practice in the field of nutritional epidemiology to analyze separate nutrients, foods, or food groups. However, in reality, nutrients and foods are consumed in combination. The introduction of dietary patterns (DP) and their analysis has revolutionized this field, making it possible to take into account the synergistic effects of foods and to account for the complex interaction among nutrients and foods. Three approaches of DP analysis exist: (1) the hypothesis-based approach (based on prior knowledge regarding the current understanding of dietary components and their health relation), (2) the exploratory approach (solely relying on dietary intake data), and (3) the hybrid approach (a combination of both approaches). During the recent past, complementary approaches for DP analysis have emerged both conceptually and methodologically. METHOD: We have summarized the recent developments that include incorporating the Treelet transformation method as a complementary exploratory approach in a narrative review. RESULTS: Uses, peculiarities, strengths, limitations, and scope of recent developments in DP analysis are outlined. Next, the narrative review gives an overview of the literature that takes into account potential relevant dietary-related factors, specifically the metabolome and the gut microbiome in DP analysis. Then the review deals with the aspect of data processing that is needed prior to DP analysis, particularly when dietary data arise from assessment methods other than the long-established food frequency questionnaire. Lastly, potential opportunities for upcoming DP analysis are summarized in the outlook. CONCLUSION: Biological factors like the metabolome and the microbiome are crucial to understand diet-disease relationships. Therefore, the inclusion of these factors in DP analysis might provide deeper insights.

Mendelian randomization analysis does not support causal associations of birth weight with hypertension risk and blood pressure in adulthood.

Epidemiology studies suggested that low birthweight was associated with a higher risk of hypertension in later life. However, little is known about the causality of such associations. In our study, we evaluated the causal association of low birthweight with adulthood hypertension following a standard analytic protocol using the study-level data of 183,433 participants from 60 studies (CHARGE-BIG consortium), as well as that with blood pressure using publicly available summary-level genome-wide association data from EGG consortium of 153,781 participants, ICBP consortium and UK Biobank cohort together of 757,601 participants. We used seven SNPs as the instrumental variable in the study-level analysis and 47 SNPs in the summary-level analysis. In the study-level analyses, decreased birthweight was associated with a higher risk of hypertension in adults (the odds ratio per 1 standard deviation (SD) lower birthweight, 1.22; 95% CI 1.16 to 1.28), while no association was found between genetically instrumented birthweight and hypertension risk (instrumental odds ratio for causal effect per 1 SD lower birthweight, 0.97; 95% CI 0.68 to 1.41). Such results were consistent with that from the summary-level analyses, where the genetically determined low birthweight was not associated with blood pressure measurements either. One SD lower genetically determined birthweight was not associated with systolic blood pressure (ß = - 0.76, 95% CI - 2.45 to 1.08 mmHg), 0.06 mmHg lower diastolic blood pressure (ß = - 0.06, 95% CI - 0.93 to 0.87 mmHg), or pulse pressure (ß = - 0.65, 95% CI - 1.38 to 0.69 mmHg, all p > 0.05). Our findings suggest that the inverse association of birthweight with hypertension risk from observational studies was not supported by large Mendelian randomization analyses.

Different domains of self-reported physical activity and risk of type 2 diabetes in a population-based Swedish cohort: the Malmö diet and Cancer study.

BACKGROUND: While a dose-response relationship between physical activity and risk of diabetes has been demonstrated, few studies have assessed the relative importance of different measures of physical activity on diabetes risk. The aim was to examine the association between different self-reported measures of physical activity and risk of type 2 diabetes in a prospective cohort study. METHODS: Out of 26,615 adults (45-74 years, 60% women) in the population-based Swedish Malmö Diet and Cancer Study cohort, 3791 type 2 diabetes cases were identified from registers during 17 years of follow-up. Leisure-time (17 activities), occupational and domestic physical activity were assessed through a questionnaire, and these and total physical activity were investigated in relation to type 2 diabetes risk. RESULTS: All physical activity measures showed weak to modest associations with type 2 diabetes risk. The strongest association was found in the lower end of leisure-time physical activity in dose-response analysis at levels approximately below 22 MET-hrs/week (300 min/week) representing around 40% of the population. Compared with the lowest quintile, the moderate leisure-time physical activity category had a 28% (95% CI: 0.71, 0.87) decreased risk of type 2 diabetes. Total physical activity showed a similar, but weaker, association with diabetes risk as to that of leisure-time physical activity. Domestic physical activity was positively and linearly related to diabetes risk, HR = 1.11 (95% CI: 0.99, 1.25) comparing highest to lowest quintile. There was no association between occupational physical activity and diabetes risk. CONCLUSION: A curvilinear association was observed between leisure-time physical activity and risk of diabetes. Beyond a threshold level of approximately 22 MET-hrs/week or 300 min/week, no additional risk reduction was observed with increase in physical activity.

Plasma kidney injury molecule-1 (p-KIM-1) levels and deterioration of kidney function over 16 years.

BACKGROUND: The kidney injury molecule-1 (KIM-1) has previously been associated with kidney function in rodents and humans. Yet its role as a predictive marker for future decline in kidney function has remained less clear. METHODS: At baseline (1991-1994), fasting plasma KIM-1 (p-KIM-1) was measured in 4739 participants of the population-based Malmö Diet and Cancer Study. Creatinine and cystatin C were used to calculate estimated glomerular filtration rate (eGFR) according to Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) Collaboration 2012 creatinine-cystatin C equation at baseline and follow-up examination (2007-2012). Incident CKD was defined as an eGFR <60 mL/min/1.73 m2 at follow-up. RESULTS: During a mean follow-up time of 16.6 years, high p-KIM-1 levels were associated with a greater decline in eGFR (quartile 1 -1.36 versus quartile 4 -1.54 mL/min/1.73 m2; P < 0.001). In multivariate analyses, the risk for incident CKD at the follow-up examination was higher among participants with baseline p-KIM-1 levels in the highest quartile {odds ratio [OR] 1.45 [95% confidence interval (CI) 1.10-1.92]} compared with those within the lowest quartile. The relative impact of baseline p-KIM-1 on incidence of CKD [OR 1.20 (95% CI 1.08-1.33) per 1 standard deviation (SD) increase in p-KIM-1] was comparable to those of age and systolic blood pressure (SBP) [OR 1.55 (95% CI 1.38-1.74) and OR 1.21 (95% CI 1.09-1.35) per 1 SD increase, respectively]. Adding p-KIM-1 to a conventional risk model resulted in significantly improved C-statistics (P = 0.04) and reclassified 9% of the individuals into the correct risk direction (continuous net reclassification improvement P = 0.02). Furthermore, the risk for hospitalization due to impaired renal function increased with increasing baseline p-KIM-1 [hazard ratio per 1 SD 1.43; (95% CI 1.18-1.74)] during a mean follow-up time of 19.2 years. CONCLUSION: Our results show that p-KIM-1 predicts the future decline of eGFR and risk of CKD in healthy middle-aged participants. Whether p-KIM-1 can be used to prioritize preventive action that needs to be further investigated.

Genetic Predisposition for Renal Dysfunction and Incidence of CKD in the Malmö Diet and Cancer Study.

BACKGROUND: Genome-wide association studies (GWAS) have identified >50 single nucleotide polymorphisms (SNP) in association with estimated glomerular filtration rate (eGFR) and chronic kidney disease (CKD) but little is known about whether the combination of these SNPs may aid in prediction of future incidence of CKD in the population. METHODS: We included 2301 participants with baseline eGFR ≥60 mL/min per 1.73 m2 from the Malmö Diet and Cancer Study-Cardiovascular Cohort. The eGFR was estimated during baseline (1991-1996) and after a mean follow-up of 16.6 years using the CKD-Epidemiology Collaboration 2009 creatinine equation. We combined 53 SNPs into a genetic risk score weighted by the effect size (wGRSCKD), and examined its association with incidence of CKD stage 3A (eGFR ≤60 mL/min per 1.73 m2). RESULTS: At follow-up, 453 study participants were defined as having CKD stage 3A. We observed a strong association between wGRSCKD and eGFR at baseline (P = 6.5 × 10-8) and at the follow-up reexamination (P = 5.0 × 10-10). The odds ratio (OR) for incidence of CKD stage 3A was 1.25 per 1 SD increment in the wGRSCKD (95% confidence interval [CI]: 1.12-1.39) adjusting for potential confounders (sex, age, body mass index [BMI], baseline eGFR, fasting glucose, systolic blood pressure (SBP), antihypertensive treatment, smoking, follow-up time). Adding wGRSCKD on the top of traditional risk factors did not improve the C-statistics (P = 0.12), but the Net Reclassification-Improvement-Index was significantly improved (cNRI = 21.3%; 95% CI: 21.2-21.4; P < 0.0001). CONCLUSION: wGRSCKD was associated with a 25% increased incidence of CKD per 1 SD increment. Although the wGRSCKD did not improve the prediction model beyond clinical risk factors per se, the information of genetic predisposition may aid in reclassification of individuals into correct risk direction.

Quality of dietary fat and genetic risk of type 2 diabetes: individual participant data meta-analysis.

OBJECTIVE: To investigate whether the genetic burden of type 2 diabetes modifies the association between the quality of dietary fat and the incidence of type 2 diabetes. DESIGN: Individual participant data meta-analysis. DATA SOURCES: Eligible prospective cohort studies were systematically sourced from studies published between January 1970 and February 2017 through electronic searches in major medical databases (Medline, Embase, and Scopus) and discussion with investigators. REVIEW METHODS: Data from cohort studies or multicohort consortia with available genome-wide genetic data and information about the quality of dietary fat and the incidence of type 2 diabetes in participants of European descent was sought. Prospective cohorts that had accrued five or more years of follow-up were included. The type 2 diabetes genetic risk profile was characterized by a 68-variant polygenic risk score weighted by published effect sizes. Diet was recorded by using validated cohort-specific dietary assessment tools. Outcome measures were summary adjusted hazard ratios of incident type 2 diabetes for polygenic risk score, isocaloric replacement of carbohydrate (refined starch and sugars) with types of fat, and the interaction of types of fat with polygenic risk score. RESULTS: Of 102 305 participants from 15 prospective cohort studies, 20 015 type 2 diabetes cases were documented after a median follow-up of 12 years (interquartile range 9.4-14.2). The hazard ratio of type 2 diabetes per increment of 10 risk alleles in the polygenic risk score was 1.64 (95% confidence interval 1.54 to 1.75, I2=7.1%, τ2=0.003). The increase of polyunsaturated fat and total omega 6 polyunsaturated fat intake in place of carbohydrate was associated with a lower risk of type 2 diabetes, with hazard ratios of 0.90 (0.82 to 0.98, I2=18.0%, τ2=0.006; per 5% of energy) and 0.99 (0.97 to 1.00, I2=58.8%, τ2=0.001; per increment of 1 g/d), respectively. Increasing monounsaturated fat in place of carbohydrate was associated with a higher risk of type 2 diabetes (hazard ratio 1.10, 95% confidence interval 1.01 to 1.19, I2=25.9%, τ2=0.006; per 5% of energy). Evidence of small study effects was detected for the overall association of polyunsaturated fat with the risk of type 2 diabetes, but not for the omega 6 polyunsaturated fat and monounsaturated fat associations. Significant interactions between dietary fat and polygenic risk score on the risk of type 2 diabetes (P>0.05 for interaction) were not observed. CONCLUSIONS: These data indicate that genetic burden and the quality of dietary fat are each associated with the incidence of type 2 diabetes. The findings do not support tailoring recommendations on the quality of dietary fat to individual type 2 diabetes genetic risk profiles for the primary prevention of type 2 diabetes, and suggest that dietary fat is associated with the risk of type 2 diabetes across the spectrum of type 2 diabetes genetic risk.

Complement C3 and incident hospitalization due to chronic kidney disease: a population-based cohort study.

BACKGROUND: Circulating C3 has been associated with diabetes and hypertension, which are the leading causes of chronic kidney disease (CKD). C3 activation is considered to contribute to several renal diseases. Here we examined whether elevated C3 concentration is associated with hospitalization due to CKD in the general population, and whether this relationship is mediated by factors such as diabetes and hypertension. METHODS: Baseline plasma C3 was quantified in 4552 participants, without previous hospital admission due to CKD, from the Malmö Diet and Cancer cohort study. Incidence of first hospitalization due to CKD (main diagnosis) was investigated in relation to C3 levels using Cox proportional hazards regression models after a mean follow-up of 19.2 ± 4.16 years. Traditional risk factors of CKD including diabetes, blood pressure, C-reactive protein and baseline renal function were considered in adjustments and sensitivity analyses. RESULTS: During the follow-up period, 94 subjects were admitted to hospital due to CKD. After multivariate adjustment, the hazard ratios (95% confidence interval) for hospitalization from CKD across quartiles of C3 were 1.00 (reference), 1.68 (0.69, 4.13), 2.71 (1.15, 6.39), and 3.16 (1.36, 7.34) (p for trend = 0.003). Results were generally consistent across different sensitivity analyses. CONCLUSIONS: These findings indicate that C3 is associated with incidence of first hospitalization due to CKD in the general population. The observed relationship cannot be entirely attributed to hyperglycemia and hypertension.

Genome-wide meta-analysis of macronutrient intake of 91,114 European ancestry participants from the cohorts for heart and aging research in genomic epidemiology consortium.

Macronutrient intake, the proportion of calories consumed from carbohydrate, fat, and protein, is an important risk factor for metabolic diseases with significant familial aggregation. Previous studies have identified two genetic loci for macronutrient intake, but incomplete coverage of genetic variation and modest sample sizes have hindered the discovery of additional loci. Here, we expanded the genetic landscape of macronutrient intake, identifying 12 suggestively significant loci (P < 1 × 10-6) associated with intake of any macronutrient in 91,114 European ancestry participants. Four loci replicated and reached genome-wide significance in a combined meta-analysis including 123,659 European descent participants, unraveling two novel loci; a common variant in RARB locus for carbohydrate intake and a rare variant in DRAM1 locus for protein intake, and corroborating earlier FGF21 and FTO findings. In additional analysis of 144,770 participants from the UK Biobank, all identified associations from the two-stage analysis were confirmed except for DRAM1. Identified loci might have implications in brain and adipose tissue biology and have clinical impact in obesity-related phenotypes. Our findings provide new insight into biological functions related to macronutrient intake.

A novel rare CUBN variant and three additional genes identified in Europeans with and without diabetes: results from an exome-wide association study of albuminuria.

AIMS/HYPOTHESIS: Identifying rare coding variants associated with albuminuria may open new avenues for preventing chronic kidney disease and end-stage renal disease, which are highly prevalent in individuals with diabetes. Efforts to identify genetic susceptibility variants for albuminuria have so far been limited, with the majority of studies focusing on common variants. METHODS: We performed an exome-wide association study to identify coding variants in a two-stage (discovery and replication) approach. Data from 33,985 individuals of European ancestry (15,872 with and 18,113 without diabetes) and 2605 Greenlanders were included. RESULTS: We identified a rare (minor allele frequency [MAF]: 0.8%) missense (A1690V) variant in CUBN (rs141640975, ß = 0.27, p = 1.3 × 10-11) associated with albuminuria as a continuous measure in the combined European meta-analysis. The presence of each rare allele of the variant was associated with a 6.4% increase in albuminuria. The rare CUBN variant had an effect that was three times stronger in individuals with type 2 diabetes compared with those without (pinteraction = 7.0 × 10-4, ß with diabetes = 0.69, ß without diabetes = 0.20) in the discovery meta-analysis. Gene-aggregate tests based on rare and common variants identified three additional genes associated with albuminuria (HES1, CDC73 and GRM5) after multiple testing correction (pBonferroni < 2.7 × 10-6). CONCLUSIONS/INTERPRETATION: The current study identifies a rare coding variant in the CUBN locus and other potential genes associated with albuminuria in individuals with and without diabetes. These genes have been implicated in renal and cardiovascular dysfunction. The findings provide new insights into the genetic architecture of albuminuria and highlight target genes and pathways for the prevention of diabetes-related kidney disease.

Dietary and genetic risk scores and incidence of type 2 diabetes.

BACKGROUND: Both lifestyle and genetic predisposition determine the development of type 2 diabetes (T2D), and studies have indicated interactions between specific dietary components and individual genetic variants. However, it is unclear whether the importance of overall dietary habits, including T2D-related food intakes, differs depending on genetic predisposition to T2D. We examined interaction between a genetic risk score for T2D, constructed from 48 single nucleotide polymorphisms identified in genome-wide association studies, and a diet risk score of four foods consistently associated with T2D in epidemiological studies (processed meat, sugar-sweetened beverages, whole grain and coffee). In total, 25,069 individuals aged 45-74 years with genotype information and without prevalent diabetes from the Malmö Diet and Cancer cohort (1991-1996) were included. Diet data were collected with a modified diet history method. RESULTS: During 17-year follow-up, 3588 incident T2D cases were identified. Both the diet risk score (HR in the highest risk category 1.40; 95% CI 1.26, 1.58; P trend = 6 × 10-10) and the genetic risk score (HR in the highest tertile of the genetic risk score 1.67; 95% CI 1.54, 1.81; P trend = 7 × 10-35) were associated with increased incidence of T2D. No significant interaction between the genetic risk score and the diet risk score (P = 0.83) or its food components was observed. The highest risk was seen among the 6% of the individuals with both high genetic and dietary risk scores (HR 2.49; 95% CI 2.06, 3.01). CONCLUSIONS: The findings thus show that both genetic heredity and dietary habits previously associated with T2D add to the risk of T2D, but they seem to act in an independent fashion, with the consequence that all individuals, whether at high or low genetic risk, would benefit from favourable food choices.

A Genome-Wide Association Study of Diabetic Kidney Disease in Subjects With Type 2 Diabetes.

Identification of sequence variants robustly associated with predisposition to diabetic kidney disease (DKD) has the potential to provide insights into the pathophysiological mechanisms responsible. We conducted a genome-wide association study (GWAS) of DKD in type 2 diabetes (T2D) using eight complementary dichotomous and quantitative DKD phenotypes: the principal dichotomous analysis involved 5,717 T2D subjects, 3,345 with DKD. Promising association signals were evaluated in up to 26,827 subjects with T2D (12,710 with DKD). A combined T1D+T2D GWAS was performed using complementary data available for subjects with T1D, which, with replication samples, involved up to 40,340 subjects with diabetes (18,582 with DKD). Analysis of specific DKD phenotypes identified a novel signal near GABRR1 (rs9942471, P = 4.5 × 10-8) associated with microalbuminuria in European T2D case subjects. However, no replication of this signal was observed in Asian subjects with T2D or in the equivalent T1D analysis. There was only limited support, in this substantially enlarged analysis, for association at previously reported DKD signals, except for those at UMOD and PRKAG2, both associated with estimated glomerular filtration rate. We conclude that, despite challenges in addressing phenotypic heterogeneity, access to increased sample sizes will continue to provide more robust inference regarding risk variant discovery for DKD.

Genome-Wide Interactions with Dairy Intake for Body Mass Index in Adults of European Descent.

SCOPE: Body weight responds variably to the intake of dairy foods. Genetic variation may contribute to inter-individual variability in associations between body weight and dairy consumption. METHODS AND RESULTS: A genome-wide interaction study to discover genetic variants that account for variation in BMI in the context of low-fat, high-fat and total dairy intake in cross-sectional analysis was conducted. Data from nine discovery studies (up to 25 513 European descent individuals) were meta-analyzed. Twenty-six genetic variants reached the selected significance threshold (p-interaction <10-7) , and six independent variants (LINC01512-rs7751666, PALM2/AKAP2-rs914359, ACTA2-rs1388, PPP1R12A-rs7961195, LINC00333-rs9635058, AC098847.1-rs1791355) were evaluated meta-analytically for replication of interaction in up to 17 675 individuals. Variant rs9635058 (128 kb 3' of LINC00333) was replicated (p-interaction = 0.004). In the discovery cohorts, rs9635058 interacted with dairy (p-interaction = 7.36 × 10-8) such that each serving of low-fat dairy was associated with 0.225 kg m-2 lower BMI per each additional copy of the effect allele (A). A second genetic variant (ACTA2-rs1388) approached interaction replication significance for low-fat dairy exposure. CONCLUSION: Body weight responses to dairy intake may be modified by genotype, in that greater dairy intake may protect a genetic subgroup from higher body weight.

Blood lipid genetic scores, the HMGCR gene and cancer risk: a Mendelian randomization study.

Background: It is unclear whether there are causal associations between blood lipids, statin use and cancer risks. Under certain assumptions, Mendelian randomization analysis of a genetic marker for an exposure eliminates reverse causation and confounding. Methods: We applied Mendelian randomization analysis to genetic scores, comprising 26-41 single-nucleotide polymorphisms (SNPs), as instrumental variables (IVs) for triglycerides and low- and high-density lipoprotein cholesterol (LDLC, HDLC), using a prospective cohort of 26 904 individuals in which there were 6607 incident cancers. We also investigated cancer risk for a SNP (rs12916) in the gene encoding hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), the targeted enzyme in statin treatment. We used logistic regression and SNP pleiotropy-adjusted analyses to estimate the odds ratio per standard deviation (OR). Results: The OR for the triglyceride IV as a predictor of any cancer was 0.91 [95% confidence interval (CI): 0.80-1.03] unadjusted, and 0.87 (95% CI: 0.78-0.95) from the pleiotropy-adjusted analysis. For the HMGCR rs12916 per LDLC-lowering T-allele, the OR was 1.09 (95% CI: 1.01-1.18) for prostate cancer and 0.89 (95% CI: 0.82-0.96) for breast cancer. The LDLC IV was not associated with prostate cancer or breast cancer. There were no associations between IVs and cancers of the lung, colon or bladder. Conclusions: Under the assumptions of Mendelian randomization, there is a causal and negative association between serum triglycerides and risk of any cancer. Further, the HMGCR genetic variant might be associated with risks of prostate and breast cancers but the biological mechanisms behind these findings are unclear, as the LDLC IV was not associated with these cancers.

Sugar-sweetened beverage intake associations with fasting glucose and insulin concentrations are not modified by selected genetic variants in a ChREBP-FGF21 pathway: a meta-analysis.

AIMS/HYPOTHESIS: Sugar-sweetened beverages (SSBs) are a major dietary contributor to fructose intake. A molecular pathway involving the carbohydrate responsive element-binding protein (ChREBP) and the metabolic hormone fibroblast growth factor 21 (FGF21) may influence sugar metabolism and, thereby, contribute to fructose-induced metabolic disease. We hypothesise that common variants in 11 genes involved in fructose metabolism and the ChREBP-FGF21 pathway may interact with SSB intake to exacerbate positive associations between higher SSB intake and glycaemic traits. METHODS: Data from 11 cohorts (six discovery and five replication) in the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) Consortium provided association and interaction results from 34,748 adults of European descent. SSB intake (soft drinks, fruit punches, lemonades or other fruit drinks) was derived from food-frequency questionnaires and food diaries. In fixed-effects meta-analyses, we quantified: (1) the associations between SSBs and glycaemic traits (fasting glucose and fasting insulin); and (2) the interactions between SSBs and 18 independent SNPs related to the ChREBP-FGF21 pathway. RESULTS: In our combined meta-analyses of discovery and replication cohorts, after adjustment for age, sex, energy intake, BMI and other dietary covariates, each additional serving of SSB intake was associated with higher fasting glucose (ß ± SE 0.014 ± 0.004 [mmol/l], p = 1.5 × 10-3) and higher fasting insulin (0.030 ± 0.005 [log e pmol/l], p = 2.0 × 10-10). No significant interactions on glycaemic traits were observed between SSB intake and selected SNPs. While a suggestive interaction was observed in the discovery cohorts with a SNP (rs1542423) in the ß-Klotho (KLB) locus on fasting insulin (0.030 ± 0.011 log e pmol/l, uncorrected p = 0.006), results in the replication cohorts and combined meta-analyses were non-significant. CONCLUSIONS/INTERPRETATION: In this large meta-analysis, we observed that SSB intake was associated with higher fasting glucose and insulin. Although a suggestive interaction with a genetic variant in the ChREBP-FGF21 pathway was observed in the discovery cohorts, this observation was not confirmed in the replication analysis. TRIAL REGISTRATION: Trials related to this study were registered at clinicaltrials.gov as NCT00005131 (Atherosclerosis Risk in Communities), NCT00005133 (Cardiovascular Health Study), NCT00005121 (Framingham Offspring Study), NCT00005487 (Multi-Ethnic Study of Atherosclerosis) and NCT00005152 (Nurses' Health Study).