Background: Iodine deficiency disorders(IDD) refer to diseases that are caused by insufficient iodine intake, and the best strategy to prevent IDD is the addition of iodine to dietary salt. Because iodine deficiency is a common cause of goiter, the prevalence as effectively controlled after the implementation of universal salt iodization(USI) in China. However, there is substantial controversy as to whether the incidence of thyroid disorders is related to iodized salt intake. Therefore, we aimed to clarify whether the risk of goiter can be promoted by USI.Methods: A longitudinal continuous study based on the national monitoring results of IDD in China was performed for 3 consecutive years. We recorded the following indicators of IDD from 31 provinces: goiter number, two degrees of goiter(the degree of goiter severity) and cretinism(three endemic diseases), iodized salt intake, median urinary iodine concentration(UIC), soil iodine content and coverage rates of iodized salt. One-way Analysis of Variance(ANOVA) and linear regression analyses examined the differences between the three groups and correlations, respectively. Data were collected from the Chinese national IDD surveillance data in 2011-2013, and the background values of Chinese soil elements were published in 1990.Results: A reference male's daily intake of maximum iodine was 378.9μg, 379.2μg and 366.9μg in 2011, 2012, and 2013, respectively. No statistical association between daily iodized salt intake and the three endemic diseases was observed in 2011-2013(P >0.05). No association was observed between daily iodized salt intake and the UIC of children in 2011(P>0.05). Linear regression revealed no significant correlation between the soil iodine content and three endemic diseases. The present study indicated no difference in the daily iodized salt intake in each province during three years(F=0.886, P=0.647). The coverage rate of iodized salt remained above 98.7%, and goiter rates were stable in 2011-2013.Conclusion: There was no significant association
Background: People rapidly ascending to high altitudes(>2500m) may suffer from acute mountain sickness(AMS). The association between smoking and AMS risk remains unclear. Therefore, we performed a meta-analysis to evaluate the association between smoking and AMS risk.Methods: The association between smoking and AMS risk was determined according to predefined criteria established by our team. Meta-analysis was conducted according to the PRISMA guidelines. We included all relevant studies listed in the Pub Med and Embase databases as of September 2015 in this meta-analysis and performed systemic searches using the terms "smoking", "acute mountain sickness" and "risk factor". The included studies were required to provide clear explanations regarding their definitions of smoking, the final altitudes reached by their participants and the diagnostic criteria used to diagnose AMS. Odds ratios(ORs) were used to evaluate the association between smoking and AMS risk across the studies, and the Q statistic was used to test OR heterogeneity, which was considered significant when P<0.05. We also computed 95% confidence intervals(CIs). Data extracted from the articles were analyzed with Review Manager 5.3(Cochrane Collaboration, Oxford, UK).Results: We used seven case-control studies including 694 smoking patients and 1986 non-smoking controls to analyze the association between smoking and AMS risk. We observed a significant association between AMS and smoking(OR=0.71, 95% CI 0.52–0.96, P=0.03).Conclusion: We determined that smoking may protect against AMS development. However, we do not advise smoking to prevent AMS. More studies are necessary to confirm the role of smoking in AMS risk.
Chen XuHong-Xiang LuYu-Xiao WangYu ChenSheng-hong YangYong-Jun Luo
Objective: Acute mountain sickness(AMS) is a common condition in individuals who ascend to altitudes over 2 500 m. There is no measurements that can reliably predict or diagnose this condition. We therefore determined whether pulse oximetry data are associated with the development of AMS and can help diagnose AMS. Methods: We studied 58 young male undergraduates who traveled from Chongqing(300 m) to Lhasa(3 658 m) by train. We collected data on the ascent profiles and AMS symptoms based on the Lake Louise Score(LLS). The resting arterial oxygen saturation(R-Sp O2) and pulse rate were then measured using finger pulse oximetry. Results: In Golmud(2 800 m) and Tanggula(5 200 m), R-SpO_2 was significantly lower in the AMS group than in the group without AMS(P<0.05). However, upon arrival in Lhasa(3 658 m), the R-SpO_2 was higher in the AMS group than in the non-AMS group(P<0.05). In Tanggula, the change in the SpO_2(CR-SpO_2) in the AMS group was higher than that in the non-AMS group(P<0.05). But in Lhasa, the CR-SpO_2 in the AMS group was lower than that in the non-AMS group(P<0.05). We also monitored heart rate(HR) throughout the study. In Xining(2 200 m) and Golmud, the HRs in the AMS group were higher than those in the non-AMS group. However, the HRs in the AMS group were lower than those in the non-AMS group in Tanggula and Lhasa. Conclusion: Based on the results of this study, the R-SpO_2 graph was not consistent. We can thus conclude that the utility of SpO_2 remains limited in the diagnosis of AMS. The results suggest that using pulse oximetry to diagnose AMS is not valuable in people ascending to Lhasa on the Qinghai-Tibet train.
Objective: Highland natives adapt well to the hypoxic environment at high altitude(HA). Several genes have been reported to be linked to HA adaptation. Previous studies showed that the endothelial nitric oxide synthase(ENOS) G894 T polymorphism contributed to the physiology and pathophysiology of humans at HA by regulating the production of NO. In this meta-analysis, we evaluate the association between the ENOS G894 T polymorphism and HA adaptation through analyzing the published data. Methods: We searched all relevant literature about the ENOS G894 T polymorphism and HA adaptation in Pub Med, Medline, and Embase before Step 2015. A random-effects model was applied(Revman 5.0), and study quality was assessed in duplicate. Six studies with 634 HA native cases and 621 low-altitude controls were included in this meta-analysis. Results: From the results, we observed that the wild-type allele G was significantly overrepresented in the HA groups(OR=1.85; 95% CI, 1.47–2.33; P<0.0001). In addition, the GG genotype was significantly associated with HA adaptation(OR=1.99; 95% CI, 1.54–2.57; P<0.0001). Conclusion: Our results showed that in 894 G allele carriers, the GG genotype might be a beneficial factor for HA adaptation through enhancing the level of NO. However, more studies were needed to confirm our findings due to the limited sample size.
