Background:Diabetic retinopathy (DR) was considered to be a common complication of diabetes. The purpose of the current study was to investigate the potential association between obesity and DR risk by conducting a meta-analysis of prospective studies.Methods:A consummate literature search of PubMed, EMBASE, and web of science was conducted until July 2016. A total of 13 prospective cohort studies were included in this meta-analysis.Results:On meta-analysis of all the studies assessing DR risk, obesity was associated with a significant increase in DR incidence (relative risk [RR], 1.20; 95% confidence interval [CI], 1.01–1.43; I2 = 59.6%). When only proliferative DR (PDR) was considered, no significant association between obesity and risk of PDR was detected. Significant harmful effect was detected in type 2 diabetes mellitus (T2DM) group (RR, 1.40; 95% CI, 1.05–1.87; I2 = 67.6%) but not mixed group (RR, 1.04; 95% CI, 0.97–1.18; I2 = 0.00%). No significant publication bias was detected in the selected 13 studies.Conclusion:Obesity was a risk factor for non-proliferative DR. However additional well-designed and well-conducted epidemiologic studies were required to deepen our understanding of the relation between obesity and DR.

BackgroundInvestigating the responses of autonomic nervous system (ANS) in hypoxia may provide some knowledge about the mechanism of neural control and rhythmic adjustment. The integrated cardiac and respiratory system display complicated dynamics that are affected by intrinsic feedback mechanisms controlling their interaction. To probe how the cardiac and respiratory system adjust their rhythms in different simulated altitudes, we studied heart rate variability (HRV) in frequency domain, the complexity of heartbeat series and cardiorespiratory phase synchronization (CRPS) between heartbeat intervals and respiratory cycles.MethodsIn this study, twelve male subjects were exposed to simulated altitude of sea level, 3000 m and 4000 m in a hypobaric chamber. HRV was assessed by power spectral analysis. The complexity of heartbeat series was quantified by sample entropy (SampEn). CRPS was determined by cardiorespiratory synchrogram.ResultsThe power spectral HRV indices at all frequency bands depressed according to the increase of altitude. The SampEn of heartbeat series increased significantly with the altitude (P < 0.01). The duration of CRPS epochs at 3000 m was not significantly different from that at sea level. However, it was significantly longer at 4000 m (P < 0.01).ConclusionsOur results suggest the phenomenon of CRPS exists in normal subjects when they expose to acute hypoxia. Further, the autonomic regulation has a significantly stronger influence on CRPS in acute hypoxia. The changes of CRPS and HRV parameters revealed the different regulatory mechanisms of the cardiac and respiratory system at high altitude.

Diabetic retinopathy (DR) is a common microvascular complication of diabetes mellitus (DM). The associations of alcohol intake with DR risk have demonstrated contradictory results. Relevant studieswere identified by searching electronic databases (Medline, EMBASE and Web of Science) until May 2016. We identified a total of 12,875 DR cases among 37,285 participants in 15 observational studies. The pooled estimation of all the included observational studies was 0.91 (95% CI, 0.79 to 1.06) in a random-effect model. Analyses stratified by study design showed no significant association between alcohol intake and DR incidence in cohort, case control or cross-sectional studies. In the subgroup analyses, neither beer nor spirits intake were associated with DR risk. Furthermore, it was interesting to find that protective effects were detected in the wine (OR = 0.77, 95% CI = 0.64 to 0.92) and sherry (OR = 0.22, 95% CI = 0.05 to 0.95) groups. In conclusion, this current meta-analysis demonstrated that alcohol intake was not associated with risk of DR. Subgroup analysis by alcoholic beverage types showed that wine consumption would reduce the incidence of DR. In the future, more large-scale prospective studies with detailed alcohol subtypes and contents are still warranted to clarify the association.Diabetes mellitus (DM) is now regarded as one of the most challenging public health problems worldwide 1 . Both the economic burden and loss of health caused by complications of DM indicate the importance of primary prevention and early intervention in the management of DM 2, 3 . Diabetic retinopathy (DR) is a common microvascular complication of DM and a major preventable cause of visual impairment in the working-age population 4 . Accordingly, early detection of DR in the DM population is crucial. The mechanisms of DR development and progression are still not fully understood 5,6 . Previous epidemiological studies indicated that longer DM duration, older age, aging and cardiovascular events were risk factors for DR incidence 7,8 .Alcohol intake is reported to be a risk factor for several kinds of diseases, including cancers, gastrointestinal diseases, respiratory disorders and infections [9][10][11] . A quantitative review of 26 epidemiological studies reported an inverse association between alcohol intake and risk of type 2 DM (T2DM) in a non-linear dose-response manner. It was found that light and moderate alcohol consumption was associated with a lower risk of T2DM, whereas heavy alcohol consumption demonstrated no protective effect against T2DM risk 12 . Furthermore, in an advanced study, specific types of alcoholic beverage consumption demonstrated modified influences on T2DM risk. In a meta-analysis of 13 prospective studies, compared with beer or spirits, wine was associated with a more significant inverse risk of DM 13 .In previous studies, the associations of alcohol intake with DR risk demonstrated contradictory results. Alcohol intake, which was regarded as an unhealthy lifestyle behavior, was previously regarded a...

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