Global meta-analysis of the C-11377G alteration in the ADIPOQ gene indicates the presence of population-specific effects: challenge for global health initiatives

Trends of mortality attributable to child and maternal undernutrition, overweight/obesity and dietary risk factors of non-communicable diseases in sub-Saharan Africa, 1990-2015: findings from the Global Burden of Disease Study 2015

OBJECTIVE

To assess trends of mortality attributable to child and maternal undernutrition (CMU), overweight/obesity and dietary risks of non-communicable diseases (NCD) in sub-Saharan Africa (SSA) using data from the Global Burden of Disease (GBD) Study 2015.

DESIGN

For each risk factor, a systematic review of data was used to compute the exposure level and the effect size. A Bayesian hierarchical meta-regression analysis was used to estimate the exposure level of the risk factors by age, sex, geography and year. The burden of all-cause mortality attributable to CMU, fourteen dietary risk factors (eight diets, five nutrients and fibre intake) and overweight/obesity was estimated.

SETTING

Sub-Saharan Africa.ParticipantsAll age groups and both sexes.

RESULTS

In 2015, CMU, overweight/obesity and dietary risks of NCD accounted for 826204 (95 % uncertainty interval (UI) 737346, 923789), 266768 (95 % UI 189051, 353096) and 558578 (95 % UI 453433, 680197) deaths, respectively, representing 10·3 % (95 % UI 9·1, 11·6 %), 3·3 % (95 % UI 2·4, 4·4 %) and 7·0 % (95 % UI 5·8, 8·3 %) of all-cause mortality. While the age-standardized proportion of all-cause mortality accounted for by CMU decreased by 55·2 % between 1990 and 2015 in SSA, it increased by 63·3 and 17·2 % for overweight/obesity and dietary risks of NCD, respectively.

CONCLUSIONS

The increasing burden of diet- and obesity-related diseases and the reduction of mortality attributable to CMU indicate that SSA is undergoing a rapid nutritional transition. To tackle the impact in SSA, interventions and international development agendas should also target dietary risks associated with NCD and overweight/obesity.

Burden of disease attributable to suboptimal diet, metabolic risks and low physical activity in Ethiopia and comparison with Eastern sub-Saharan African countries, 1990-2015: findings from the Global Burden of Disease Study 2015

BACKGROUND

Twelve of the 17 Sustainable Development Goals (SDGs) are related to malnutrition (both under- and overnutrition), other behavioral, and metabolic risk factors. However, comparative evidence on the impact of behavioral and metabolic risk factors on disease burden is limited in sub-Saharan Africa (SSA), including Ethiopia. Using data from the Global Burden of Disease (GBD) Study, we assessed mortality and disability-adjusted life years (DALYs) attributable to child and maternal undernutrition (CMU), dietary risks, metabolic risks and low physical activity for Ethiopia. The results were compared with 14 other Eastern SSA countries.

METHODS

Databases from GBD 2015, that consist of data from 1990 to 2015, were used. A comparative risk assessment approach was utilized to estimate the burden of disease attributable to CMU, dietary risks, metabolic risks and low physical activity. Exposure levels of the risk factors were estimated using spatiotemporal Gaussian process regression (ST-GPR) and Bayesian meta-regression models.

RESULTS

In 2015, there were 58,783 [95% uncertainty interval (UI): 43,653-76,020] or 8.9% [95% UI: 6.1-12.5] estimated all-cause deaths attributable to CMU, 66,269 [95% UI: 39,367-106,512] or 9.7% [95% UI: 7.4-12.3] to dietary risks, 105,057 [95% UI: 66,167-157,071] or 15.4% [95% UI: 12.8-17.6] to metabolic risks and 5808 [95% UI: 3449-9359] or 0.9% [95% UI: 0.6-1.1] to low physical activity in Ethiopia. While the age-adjusted proportion of all-cause mortality attributable to CMU decreased significantly between 1990 and 2015, it increased from 10.8% [95% UI: 8.8-13.3] to 14.5% [95% UI: 11.7-18.0] for dietary risks and from 17.0% [95% UI: 15.4-18.7] to 24.2% [95% UI: 22.2-26.1] for metabolic risks. In 2015, Ethiopia ranked among the top four countries (of 15 Eastern SSA countries) in terms of mortality and DALYs based on the age-standardized proportion of disease attributable to dietary and metabolic risks.

CONCLUSIONS

In Ethiopia, while there was a decline in mortality and DALYs attributable to CMU over the last two and half decades, the burden attributable to dietary and metabolic risks have increased during the same period. Lifestyle and metabolic risks of NCDs require more attention by the primary health care system of the country.

Genetic risk of type 2 diabetes in populations of the African continent: A systematic review and meta-analyses

BACKGROUND

Type 2 diabetes (T2D) is growing faster in Africa than anywhere else, driven by the dual effects of genetic and environmental factors. We conducted a systematic review and meta-analyses of published studies on genetic markers of T2D in populations within Africa.

METHODS

Multiple databases were searched for studies of genetic variants associated with T2D in populations living in Africa. Studies reporting on the association of a genetic marker with T2D or indicators of glycaemia were included. Data were extracted on study design and characteristics, genetic determinants, effect estimates of associations with T2D.

FINDINGS

Overall, 100 polymorphisms in 57 genes have been investigated in relation with T2D in populations within Africa, in 60 studies. Almost all studies used the candidate gene approach, with >88% published during 2006-2014 and 70% (42/60) originating from Tunisia and Egypt. Polymorphisms in ACE, AGRP, eNOS, GSTP1, HSP70-2, MC4R, MTHFR, PHLPP, POL1, TCF7L2, and TNF-α gene were found to be associated with T2D, with overlapping effect on various cardiometabolic traits. The polymorphisms investigated in multiple studies mostly had consistent effects across studies, with only modest or no statistical heterogeneity. Effect sizes were modestly significant [e.g., odd ratio 1.49 (95%CI 1.33-1.66) for TCF7L2 (rs7903146)]. Underpowered genome-wide studies revealed no diabetes risk loci specific to African populations.

INTERPRETATION

Current evidence on the genetic markers of T2D in African populations mostly originate from North African countries, is overall scanty and largely insufficient to reliably inform the genetic architecture of T2D across Africa.

Short-term effects of fish and fish oil consumption on total and high molecular weight adiponectin levels in overweight and obese adults

OBJECTIVE

Fish or fish oil consumption may increase levels of total and high molecular weight (HMW) adiponectin, a hormone associated with anti-inflammatory and insulin-sensitising effects, however it is not known if the effects of the food and supplement are the same. The aim of this study was to compare the effect of consuming fish and fish oil supplements on plasma total and HMW adiponectin concentrations in overweight human participants.

MATERIALS/METHODS

29 overweight and obese participants underwent a two week run-in period, followed by a four week isocaloric dietary intervention which provided 1.8 g of long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) in the form of either fish or fish oil supplements. Primary outcomes were changes in plasma total and HMW adiponectin. Secondary outcomes were changes in anthropometric variables, plasma insulin and glucose levels, and dietary intakes.

RESULTS

Changes in plasma HMW adiponectin during the intervention period were significantly different between groups (p=0.009). Mean HMW adiponectin increased by 0.29 μg/mL in the 'fish' group and decreased by 0.60 μg/mL in the 'supplement' group. There were no significant changes in other anthropometric and biochemical variables. Dietary data suggested the 'fish' group significantly increased their fish (p=0.001) and dietary LC n-3 PUFA (p=0.001) consumption over the course of the study.

CONCLUSIONS

Short-term consumption of fish and fish oil supplements did not have the same effects on HMW adiponectin levels. The impact of fish intake on HMW adiponectin levels may not be mediated by its LC n-3 PUFA content alone.

Common variants in genes encoding adiponectin (ADIPOQ) and its receptors (ADIPOR1/2), adiponectin concentrations, and diabetes incidence in the Diabetes Prevention Program

AIMS

Baseline adiponectin concentrations predict incident Type 2 diabetes mellitus in the Diabetes Prevention Program. We tested the hypothesis that common variants in the genes encoding adiponectin (ADIPOQ) and its receptors (ADIPOR1, ADIPOR2) would associate with circulating adiponectin concentrations and/or with diabetes incidence in the Diabetes Prevention Program population.

METHODS

Seventy-seven tagging single-nucleotide polymorphisms (SNPs) in ADIPOQ (24), ADIPOR1 (22) and ADIPOR2 (31) were genotyped. Associations of SNPs with baseline adiponectin concentrations were evaluated using linear modelling. Associations of SNPs with diabetes incidence were evaluated using Cox proportional hazards modelling.

RESULTS

Thirteen of 24 ADIPOQ SNPs were significantly associated with baseline adiponectin concentrations. Multivariable analysis including these 13 SNPs revealed strong independent contributions of rs17366568, rs1648707, rs17373414 and rs1403696 with adiponectin concentrations. However, no ADIPOQ SNPs were directly associated with diabetes incidence. Two ADIPOR1 SNPs (rs1342387 and rs12733285) were associated with ∼18% increased diabetes incidence for carriers of the minor allele without differences across treatment groups, and without any relationship with adiponectin concentrations.

CONCLUSIONS

  ADIPOQ SNPs are significantly associated with adiponectin concentrations in the Diabetes Prevention Program cohort. This observation extends prior observations from unselected populations of European descent into a broader multi-ethnic population, and confirms the relevance of these variants in an obese/dysglycaemic population. Despite the robust relationship between adiponectin concentrations and diabetes risk in this cohort, variants in ADIPOQ that relate to adiponectin concentrations do not relate to diabetes risk in this population. ADIPOR1 variants exerted significant effects on diabetes risk distinct from any effect of adiponectin concentrations.

Genetic association of adiponectin with type 2 diabetes in Jordanian Arab population

Adiponectin, a protein exclusively secreted by adipose tissue and present at low levels in obese individuals, is now widely recognized as a key determinant of insulin sensitivity and protection against obesity-associated metabolic syndrome. In Jordan, prevalence of diabetes (17.1%) is twice that of the United States (7.8%). In this study, we examined the contribution of the promoter variant rs266729 (-11377C>G) of the ADIPOQ gene as a risk factor for diabetic patients in Jordan. DNA was extracted from blood samples for patients and controls .Polymerase chain reaction and restriction fragment length polymorphism were used to genotype this variant. A total of 420 type 2 diabetic patients and 230 controls were successfully genotyped. The results showed a significant genotypic (p=0.00001) and allelic (p=0.01) association with variant in the diabetic patients as compared to controls. This suggests that the ADIPOQ gene plays a major role in increasing the risk of diabetes, at least in the Jordanian Arab population.

The association studies of ADIPOQ with type 2 diabetes mellitus in Chinese populations

Adiponectin, which is secreted by the white adipose tissue, plays an important role in type 2 diabetes mellitus (T2DM) and its complications. Since 2002, many investigators explored the association between ADIPOQ single nucleotide polymorphisms and T2DM in different ethnic populations from different regions. In China, the results of numerous studies of the association between ADIPOQ and T2DM were not consistent, which may be caused by population-specific effects or environmental effects. This review describes the association between ADIPOQ and T2DM, the metabolic characteristics and the complications of T2DM in Chinese populations.

The nutrition transition in Africa: can it be steered into a more positive direction?

The objective of this narrative review is to examine the nutrition transition and its consequences when populations in Africa modernize as a result of socio-economic development, urbanization, and acculturation. The focus is on the changes in dietary patterns and nutrient intakes during the nutrition transition, the determinants and consequences of these changes as well as possible new approaches in public health nutrition policies, interventions and research needed to steer the nutrition transition into a more positive direction in Africa. The review indicates that non-communicable, nutrition-related diseases have emerged in sub-Saharan Africa at a faster rate and at a lower economic level than in industrialized countries, before the battle against under-nutrition has been won. There is a putative epigenetic link between under- and over-nutrition, explaining the double burden of nutrition-related diseases in Africa. It is concluded that it is possible to steer the nutrition transition into a more positive direction, provided that some basic principles in planning public health promotion strategies, policies and interventions are followed. It is suggested that sub-Saharan African countries join forces to study the nutrition transition and implemented interventions on epidemiological, clinical and molecular (genetic) level for better prevention of both under- and over-nutrition.

Genetic effects of adiponectin on blood lipids and blood pressure

OBJECTIVE

Results from the published studies on the association of adiponectin gene (ADIPOQ) polymorphisms with blood lipids and blood pressure are conflicting. We investigated the association of three ADIPOQ polymorphisms, +45 T > G (rs2241766), +276 G > T (rs1501299) and -11377 C > G (rs266729), with these traits in this meta-analysis.

RESEARCH DESIGN AND METHODS

We included 35 studies in this meta-analysis. Dominant models were used for this meta-analysis.

RESULTS

We did not detect a significant association of the -11377 C > G polymorphism with blood lipids or blood pressure (P > 0·05). The association of the +45 T > G polymorphism with blood lipids and blood pressure was, similarly, not significant (P > 0·05). The meta-analysis suggested a significant overall association of the +276 G > T polymorphism with lower levels of total cholesterol: weighted mean difference (WMD) = -0·10, 95% confidence interval (CI, -0·17, -0·03), P = 0·005, P(heterogeneity)  = 0·04. This association was marginally significant in East Asians and East Asians with type 2 diabetes: WMD = -0·10, 95% CI (-0·20, 0·00), P = 0·05, P(heterogeneity)  = 0·002, and WMD = -0·09, 95% CI (-0·18, -0·00), P = 0·05, P(heterogeneity)  = 0·80, respectively. After exclusion of a study that was the source of heterogeneity, the association was significant in overall populations and marginally significant in East Asians: WMD= -0·06, 95% CI (-0·11, -0·01), P = 0·01, P(heterogeneity)  = 0·98, and WMD = -0·06, 95% CI (-0·12, 0·00), P = 0·07, P(heterogeneity)  = 0·83, respectively. However, none of these associations were significant after Bonferroni correction (significant threshold: P < 0·003).

CONCLUSIONS

Our meta-analysis does not suggest any association of the three ADIPOQ polymorphisms with blood lipids and blood pressure.

Common variation at the adiponectin locus is not associated with colorectal cancer risk in the UK

A recent study examined common genetic variants at the adiponectin locus (ADIPOQ) in two case-control colorectal cancer (CRC) series from the USA and reported a positive association between a single nucleotide polymorphism (SNP) in the 5' region of the gene (rs266729) and decreased disease risk. In an attempt to replicate the previously reported association, we examined data from two CRC genome-wide association studies based on the UK population. The first cohort comprised 931 familial colorectal tumour cases and 929 cancer-free controls. The second included 1216 individuals with Dukes stage B or C CRCs from two clinical trials and 1436 controls from the 1958 Birth Cohort. We tested associations between CRC risk and 82 SNPs in a region of 250 kb around the ADIPOQ gene; nine of these SNPs were located in the coding and promoter regions. None of the markers tested was significantly associated with CRC risk after correction for multiple testing under any of the models in any of the two cohorts. A meta-analysis of the data also failed to detect any association. We, therefore, failed to replicate an association between common variants at ADIPOQ and CRC risk in the UK, and suggest that the previous report is either population-specific or a false-positive result.

An update on preventive and regenerative therapies in diabetes mellitus

Type 1A (immune-mediated) and type 2 diabetes mellitus are two of the most common severe chronic illnesses, affecting over 230 million people worldwide with an estimated global prevalence of 5.1%. Although type 1 and type 2 diabetes differ greatly in modes of pathogenesis, these illnesses share a common pathology and consequences characterized by loss of functional beta-cell mass and subsequent dysregulation of carbohydrate and lipid metabolism. Since therapy for diabetes and the associated complications poses enormous public health and economic burdens, novel preventive and regenerative therapies have emerged in the past decade with the aim to preserve beta-cell mass and delay the onset of diabetes. The goal of this review is to provide a comprehensive overview of current efforts in the fight against diabetes, and attempts to document all strategies that have emerged in clinical studies within the past 25 years. First, strategies to identify individuals at risk, ranging from whole-genome scans to autoantibody screening, will be discussed. Second, novel approaches to prevent or delay the onset of disease will be covered. Particular focus is given on emerging strategies for individuals at risk for type 1 diabetes that target T-cell regulation and induction of tolerance, while new pharmaceutical concepts in combination with lifestyle interventions are discussed within the scope of type 2 diabetes prevention. Lastly, important efforts to halt disease progression with emphasis on beta-cell regeneration are presented.