The Relationship Between Physical Activity And Kir Gene And Blood Pressure Salt Sensitivity And The Incidence Of Hypertension

Background and Objective Hypertension is an important risk factor of morbidity and mortality of cardiovascular and renal diseases and has become a serious public health problem.Physical activity(PA)is a risk factor of hypertension that could be controlled by individuals.Recently,the level of PA in Chinese residents,especially in rural areas,is declining significantly.This study aims to investigate the relationship between physical activity and the risk of incident hypertension among population from rural area of China.Subjects and Methods The Community Intervention of Metabolic Syndrome in China&Chinese Family Health Study(CIMIC)was conducted in 2007-2008.Data on PA,smoking,drinking,blood pressure(BP)and other variables were obtained at baseline.Then the follow-up study of incident hypertension was performed during 2012-2015.A total of 41457 participants aged>18 years and free from hypertension at baseline were included in the final analyses.Total PA was calculated as metabolic equivalent(MET)for each participant.Participants were grouped according to quartiles of total PA or time of moderate and vigorous PA.Cox proportional hazard models were used to explore the relationships of total PA,time of moderate and vigorous PA and PA intensity at work with incident hypertension.Results A total of 6780 participants developed hypertension during an average follow up of 5.8 years.The annual incidence of hypertension was 2.80%.After adjusting age,gender,body mass index(BMI),region,education,smoking and drinking status,fasting blood glucose,total cholesterol and baseline systolic BP,compared to participants in the first quartile of total PA,hazard ratio(HR)and 95%confidence interval(CI)of incident hypertension decreased with the increase of the level of total PA,which were 0.92(0.86,0.99),0.72(0.67,0.77)and 0.70(0.65,0.75)for the 2nd,3rd and 4th quartiles,respectively(Ptrend<0.001).Results of subgroup analyses in different gender,BP at baseline,BMI and central obesity status were similar.Compared to the first quartile of total PA,hazards of hypertension were decreased with the increase of the level of total PA.Compared to the first quartile of the time of moderate and vigorous PA,HR(95%CI)of incident hypertension decreased with the increase of the time of moderate and vigorous PA,which were 0.84(0.78,0.90),0.74(0.70,0.79)and 0.63(0.59,0.68)for the 2nd,3rd and 4th quartiles,respectively.Compared to the lightest PA intensity at work,HR(95%CI)of incident hypertension decreased in the moderate or heavy PA intensity at work,which were 0.93(0.82,1.05)and 0.72(0.63,0.81),respectively.However,the difference in the risk of incident hypertension was not statistically significant between the groups of the lightest and moderate PA intensity at work.Conclusion There is a linear trend association between total PA and incident hypertension in China rural area.Incident hypertension decreased with the increase of total PA.Hazard of incident hypertension in men with total PA>79.44 MET·h/d or women with total PA>68.54 MET·h/d was 30%less than the lowest quartile.Furthermore,the more time of moderate and vigorous PA was an independent protective factor of incident hypertension.Therefore,increased PA in daily life is strongly recommended as a protective factor against hypertension in China rural area.Background and Objective Blood pressure(BP)responses to dietary sodium intervention vary among individuals,termed as blood pressure salt sensitivity.Potassium supplementation can reduce BP in salt-sensitive but not salt-resistant individuals.Inwardly rectifying potassium channel(Kir)is a potassium selective ion channels that is found in various types of cells,which allows potassium ions to move more easily into rather than out of the cell.The present study aims to investigate the associations of Kir genes with BP responses to dietary sodium intervention.Subjects and Methods A 7-day low-sodium intervention followed by a 7-day high-sodium intervention was conducted among 1906 participants.BP measurements were obtained at baseline and during each dietary intervention.1871(98.2%)participants completed the low-sodium intervention while 1860(97.6%)completed the high-sodium intervention.Mix-effect models for single-marker analyses and truncated product method(TPM)for gene-based analyses were used to explore the associations between variants of Kir genes and BP responses to dietary sodium intervention.Results During the low-sodium intervention,markers rs858009,rs2835904 and rs860795 in KCNJ6 were significantly associated with systolic BP(SBP)response(P=8.82×10-6,3.32×10-6 and 2.39×10-4,respectively)while rs858009 and rs2835904 were significantly correlated with mean arterial pressure(MAP)response(P=1.64×10-4 and 2.72×10-4,respectively).And marker rs2836023 showed a significant association with SBP response(P=5.72×10-5)to high-sodium intervention.Gene-based analyses consistently revealed that KCNJ6 was significantly associated with SBP,DBP and MAP response to low-sodium intervention and SBP response to high-sodium intervention(all P<1.00×10-6).Conclusion This study found that Kir genes may contribute to the variation of BP responses to dietary sodium intervention.Future studies are warranted to confirm these findings and to identify functional variants for salt sensitivity.