Circulating calcium levels and the risk of type 2 diabetes: a systematic review and meta-analysis.

Abnormal Ca homeostasis has been associated with impaired glucose metabolism. However, the epidemiological evidence is controversial. We aimed to assess the association between circulating Ca levels and the risk of type 2 diabetes mellitus (T2DM) or abnormal glucose homeostasis through conducting a systematic review and meta-analysis. Eligible studies were identified by searching electronic database (PubMed, Embase and Google Scholar) and related references with de novo results from primary studies up to December 2018. A random-effects meta-analysis was performed to estimate the weighted relative risks (RR) and 95 % CI for the associations. The search yielded twenty eligible publications with eight cohort studies identified for the meta-analysis, which included a total of 89 165 participants. Comparing the highest with the lowest category of albumin-adjusted serum Ca, the pooled RR was 1·14 (95 % CI 1·05, 1·24) for T2DM (n 51 489). Similarly, serum total Ca was associated with incident T2DM (RR 1·25; 95 % CI 1·10, 1·42) (n 64 502). Additionally, the adjusted RR for 1 mg/dl increments in albumin-adjusted serum Ca or serum total Ca levels was 1·16 (95 % CI 1·07, 1·27) and 1·19 (95 % CI 1·11, 1·28), respectively. The observed associations remained with the inclusion of a cohort study with ionised Ca as the exposure. However, data pooled from neither case-control (n 4) nor cross-sectional (n 8) studies manifested a significant correlation between circulating Ca and glucose homeostasis. In conclusion, accumulated data from the cohort studies suggest that higher circulating Ca levels are associated with an augmented risk of T2DM.

Vegetarians have a lower fasting insulin level and higher insulin sensitivity than matched omnivores: A cross-sectional study.

BACKGROUND AND AIMS: Potential associations of vegetarian diet patterns with fasting insulin (FI) and insulin sensitivity remain unclear. We aimed to investigate whether vegetarian diets were associated with FI and insulin sensitivity in a cross-sectional study in Chinese vegetarians and matched omnivores and then to test whether it is independent of body mass index (BMI). METHODS AND RESULTS: This study included 279 vegetarians (73 vegans, 206 lacto-ovo-vegetarians) and 279 age- and sex-matched omnivores. Fasting blood glucose (FG) and FI concentrations were measured, and ß-cell function (HOMA-ß) and insulin resistance index (HOMA-IR) were used to evaluate insulin sensitivity. All blood glucose and insulin sensitivity indices were naturally log-transformed, and multiple-linear regression was used to determine the association between vegetarian diet patterns and insulin sensitivity after adjusting for confounders including BMI, visceral fat area, physical activity, sedentary time, income, alcohol consumption, and daily dietary intakes of macronutrients. Compared to omnivores, both vegan diet [ß = -0.25, 95% CI: (-0.38, -0.14)] and lacto-ovo-vegetarian diet [ß = -0.10, 95% CI: (-0.18, -0.01)] were negatively associated with HOMA-IR after adjusting for BMI. Vegan diet remained negatively associated with FI [ß = -0.16, 95% CI: (-0.30, -0.01)] and HOMA-IR [ß = -0.17, 95% CI: (-0.32, -0.03)] after adjusting for all confounders. CONCLUSION: Vegetarian diet, especially vegan diet, is negatively associated with FI and IR, independent of BMI.

Dietary magnesium intake and risk of metabolic syndrome: a meta-analysis.

AIMS: To estimate quantitatively the association between dietary magnesium intake and risk of metabolic syndrome by combining the relevant published articles using meta-analysis. METHODS: We reviewed the relevant literature in PubMed and EMBASE published up until August 2013 and obtained additional information through Google or a hand search of the references in relevant articles. A random-effects or fixed-effects model, as appropriate, was used to pool the effect sizes on metabolic syndrome comparing individuals with the highest dietary magnesium intake with those having the lowest intake. The dose-response relationship was assessed for every 100-mg/day increment in magnesium intake and risk of metabolic syndrome. RESULT: Six cross-sectional studies, including a total of 24 473 individuals and 6311 cases of metabolic syndrome, were identified as eligible for the meta-analysis. A weighted inverse association was found between dietary magnesium intake and the risk of metabolic syndrome (odds ratio 0.69, 95% CI 0.59, 0.81) comparing the highest with the lowest group. For every 100-mg/day increment in magnesium intake, the overall risk of having metabolic syndrome was lowered by 17% (odds ratio 0.83, 95% CI 0. 77, 0.89). CONCLUSION: Findings from the present meta-analysis suggest that dietary magnesium intake is inversely associated with the prevalence of metabolic syndrome. Further studies, in particular well-designed longitudinal cohort studies and randomized placebo-controlled clinical trials, are warranted to provide solid evidence and to establish causal inference.

Fish oil, selenium and mercury in relation to incidence of hypertension: a 20-year follow-up study.

OBJECTIVES: Long-chain omega-3 polyunsaturated fatty acids (LCω3PUFAs), selenium (Se) and mercury (Hg) are three important components in fish. The cardioprotective effect of LCω3PUFA intake has been recognized; however, the hypothesis that this benefit may be greatest with high Se and low Hg levels has not been investigated. DESIGN: A cohort of 4508 American adults aged 18-30, without hypertension at baseline in 1985, were enrolled. Six follow-ups were conducted at examinations in 1987, 1990, 1992, 1995, 2000 and 2005. Diet was assessed by a validated interviewer-administered quantitative food frequency questionnaire at exams in 1985, 1992 and 2005. Incident hypertension was defined as first occurrence at any follow-up examination of systolic blood pressure (BP) ≥ 140 mmHg, diastolic BP ≥ 90 mmHg or taking antihypertensive medication. Toenail clippings were collected in 1987, and Se and Hg levels were quantified by instrumental neutron-activation analysis. RESULT: Participants in the highest LCω3PUFA intake quartile had a significantly lower incidence of hypertension (hazard ratio: 0.65; 95% CI: 0.53-0.79; P(trend) < 0.01) compared to those in the lowest quartile after adjustment for potential confounders. Docosahexaenoic acid showed a greater inverse association than eicosapentaenoic acid. The inverse association of LCω3PUFA intake with hypertension appeared more pronounced at higher Se and lower Hg levels, although interaction tests were statistically nonsignificant. CONCLUSIONS: Our findings indicated that LCω3PUFA intake was inversely associated with incidence of hypertension. The prior hypothesis that the potential antihypertensive effect of LCω3PUFA intake varies depending on joint levels of Se and Hg received modest support and cannot be ruled out.

Association between renin-angiotensin system gene polymorphism and essential hypertension: a community-based study.

Renin-angiotensin (RAS) genes, a group of promising candidate genes involved in essential hypertension (EH), play a key role in blood pressure regulation. Recently, a series of novel RAS gene polymorphisms were reported, which significantly influence the rate of the gene transcription. This study was designed to explore the association between the RAS gene polymorphisms and EH in a remote countryside population. We examined six polymorphisms in the main component genes of RAS: angiotensin-converting enzyme (ACE) (I/D), angiotensinogen (AGT) (A-6G, A-20C, G-217A and T174 M) and angiotensin type 1 receptor (AT1R) (A1166C). Six polymorphisms were genotyped by gene chip technology. Association studies were performed in 220 EH patients and 235 normotensives. Our results revealed that AGT A-6G, T174 M and ACE-I/D were significantly associated with EH (AGT A-6G: AG+GG vs AA; OR=1.36; 95% CI=1.04-1.77. T174M: CT+TT vs CC; OR=1.45; 95% CI=1.15-1.90. ACE I/D: ID+DD vs II; OR=1.171; 95% CI=1.00-1.37). Moreover the logistic regression analysis suggested that the haplotype of AGT -6A, 174C, -217G and -20A might decrease the risk of EH (OR=0.64; 95% CI=0.49-0.83), after adjusting the confounding factors of gender, age and BMI. In conclusion, the AGT A-6G, T174 M and ACE I/D polymorphisms are associated with EH and the AGT haplotype -6A, 174C, -217G and -20A decrease the risk of EH in the southern Chinese population.

Long-term association between dairy consumption and risk of childhood obesity: a systematic review and meta-analysis of prospective cohort studies.

BACKGROUND/OBJECTIVES: Data from small-scale, short-term, clinical trials suggest a beneficial effect of dairy consumption on the risk of childhood obesity; however, the long-term association is unclear. Therefore, we aim to examine the longitudinal association between dairy consumption and the risk of overweight/obesity in children and adolescents by conducting a systematic review and meta-analysis of prospective cohort studies. SUBJECTS/METHODS: Eligible studies were identified by searching PubMed and EMBASE through March 2015. Additional studies were retrieved via Google Scholar or a hand review of the reference lists from relevant articles. Pooled associations of interest were estimated by using a random-effects model. The heterogeneity for each pooled analysis was evaluated by I(2) statistic as well as by Cochran's Q test. Publication bias was assessed by using both Egger's and Begg's tests. RESULTS: Ten studies comprising 46,011 children and adolescents with an average 3-year follow-up were included. As compared with those who were in the lowest group of dairy consumption, children in the highest intake group were 38% less likely to have childhood overweight/obesity (pooled odds ratio (OR)=0.62; 95% confidence interval (CI): 0.49, 0.80). With each 1 serving/day increment in dairy consumption, the percentage of body fat was reduced by 0.65% (ß=0.65; 95% CI: -1.35, 0.06; P=0.07), and the risk of overweight/obesity was 13% lower (OR=0.87; 95% CI: 0.74, 0.98). CONCLUSIONS: Accumulated evidence from prospective cohort studies suggests that dairy consumption is inversely and longitudinally associated with the risk of childhood overweight/obesity. Further studies are warranted to examine the types of dairy products in relation to the risk of childhood overweight/obesity.

Corrigendum. Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review.

Correction to: European Journal of Clinical Nutrition (2014) 68, 510­516; doi:10.1038/ejcn.2014.7; published online 12 February 2014 Since the publication of this article the authors have noticed an error in the first sentence of the last paragraph of the results section. The sentence should be: In addition, five Mg intervention studies (Table 2) reported on the association between Mg supplementation and serum CRP levels. The authors apologize for any inconvenience caused.

Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review.

BACKGROUND/OBJECTIVES: The aim of this study was to quantitatively summarize the association of dietary magnesium (Mg) intake with serum C-reactive protein (CRP) levels in the general population. SUBJECTS/METHODS: Observational and experimental studies through February 2013 were reviewed in PubMed and EMBASE. Additional information was retrieved through Google or hand search of related reference lists. The main outcome is either adjusted geometric mean of CRP or odds ratio (OR) of having serum CRP ≥ 3 mg/l. Meta-regression was used to determine the linear association of dietary Mg intake and adjusted geometric means of CRP levels. A fixed-effects model was used to pool ORs of interest, comparing those in the lowest with those in the highest group of dietary Mg intake. RESULTS: A data set derived from seven cross-sectional studies including 32,918 participants was quantitatively assessed. A weighted inverse association between Mg intake and serum CRP levels was observed (ß-coefficient: -0.0028; 95% confidence interval (CI), -0.0043 to -0.0013; P(trend) = 0.001) from four cross-sectional studies. The pooled OR (95% CI) of having CRP ≥ 3 mg/l was 1.49 (1.18-1.89) on comparing the lowest to the highest group of Mg intake from three studies with the data available. Qualitative assessment among five intervention studies also showed a potential beneficial effect of Mg intake on serum CRP levels. CONCLUSIONS: This meta-analysis and systematic review indicates that dietary Mg intake is significantly and inversely associated with serum CRP levels. The potential beneficial effect of Mg intake on chronic diseases may be, at least in part, explained by inhibiting inflammation.

Fish consumption and risk of stroke and its subtypes: accumulative evidence from a meta-analysis of prospective cohort studies.

BACKGROUND/OBJECTIVES: To provide a reliable assessment of the hypothesized association of fish consumption with stroke risk accumulatively, an updated meta-analysis of published prospective cohort studies was conducted. SUBJECTS/METHODS: Prospective cohort studies through April 2012 in peer-reviewed journals indexed in MEDLINE and EMBASE were selected. Additional information was retrieved through Google or a search of the reference list in relevant articles. The main outcome measure was the weighted hazards ratio (HR) and corresponding 95% confidence interval (CI) for incident stroke according to fish consumption using a random-effects model. RESULTS: A database was derived from 16 eligible studies (19 cohorts), including 402,127 individuals (10,568 incident cases) with an average 12.8 years of follow-up. Compared with those who never consumed fish or ate fish <1/month, the pooled adjusted HRs of total stroke risk were 0.97 (95% CI, 0.87-1.08), 0.86 (0.80-0.93), 0.91 (0.85-0.98) and 0.87 (0.79-0.96) for those who consumed fish 1-3/month, 1/week, 2-4/week and ~5/week, respectively (P(linear trend) = 0.09; P(nonlinear trend) = 0.02). Study location was a modifier. An inverse association between fish intake and stroke incidence was only found by studies conducted in North America. The modest inverse associations were more pronounced with ischemic stroke and were attenuated with hemorrhagic stroke. CONCLUSIONS: Accumulated evidence generated from this meta-analysis suggests that fish intake may have a protective effect against the risk of stroke, particularly ischemic stroke.

Prevalence and causes of visual impairment among the elderly in Nantong, China.

PURPOSE: To investigate the prevalence and causes of visual impairment among adults aged 60 and above in Nantong city, China. METHODS: A stratified random sampling was used to select the people from eight communities in Xinchengqiao administrative sub-district of Nantong. The eye examinations were conducted at the community activity centres. The definitions of visual impairment were based on the pinhole visual acuity (low vision: visual acuity <6/18 to 3/60 in the better eye; blindness: visual acuity <3/60 in the better eye). Prevalence of visual impairment based on presenting visual acuity was also calculated. Both univariate and multiple analysis were used to do the statistics. RESULTS: A total of 3040 (90.69%) out of 3352 enumerated subjects participated in the survey. The prevalence of blindness and low vision based on the pinhole visual acuity was 1.35% (presenting, 1.32%) and 1.84% (presenting, 6.05%) respectively. The prevalence of blindness and low vision grew up exponentially with age (R2=0.9993, F=1385.84, P=0.0007; R2=0.9949, F=195.65, P=0.0051) and down with increasing education level (score test for trend of odds: chi2=30.35, P=0.0000; chi2=22.31, P=0.0000), and was higher among women than men (LR chi2=9.62, P=0.0019; LR chi(2)=5.14, P=0.0234). CONCLUSIONS: Blindness and low vision were prevalent in the urban area of China, especially in the elderly women, with cataract the most common cause in the Chinese elderly. Therefore, our study highlights an urgent necessity for launching some programs for blindness and low vision prevention, especially on the early treatment of cataract.