Differences in genotype frequencies of salt-sensitive genes between fishing and nonfishing communities in Japan

PURPOSE: To identify the differences in genotype frequencies of salt-sensitive genes between residents of fishing communities (FCs) and nonfishing communities (NFCs). METHODS: The subjects included 18,156 individuals (8,043 males [44%] and 10,113 females [56%]; average age: 57.2±16.1 years) from the general population who were registered with large-scale genome banks and resided in 30 prefectures and 78 different regions in Japan. The measurement items were age, sex, blood pressure, presence or absence of hypertension, body mass index, alcohol consumption, and smoking habit. Furthermore, to analyze the genotype frequencies of salt-sensitive genes, α-adducin 1 (ADD1), angiotensinogen (AGT), angiotensin II receptor type 1 (AT1), and guanine nucleotide-binding protein β peptide 3 (GNB3) were measured. According to the 2004 government classification of municipalities (cities, towns, and villages), communities existing in areas bordering an ocean and with an ocean port were defined as FCs (28 areas). The others were defined as NFCs (50 areas). A logistic regression model was used for comparison of genotype frequencies between subjects residing in FCs and NFCs. RESULTS: Of the included subjects, 4,916 (27.0%) and 13,240 (73.0%) resided in FCs and NFCs, respectively. In FCs, the mean age was 59.4±16.7 years and men accounted for 41.0% of the cohort (n=2,015). In NFCs, the mean age was 56.4±15.8 years and men accounted for 45.5% of the cohort (n=6,028). The adjusted odds ratios of the AA and AG genotypes compared with the GG genotype for AGT were 0.80 (95% confidence interval [CI]: 0.68–0.95) and 0.76 (95% CI: 0.64–0.91), respectively. The adjusted odds ratio of the CC genotype compared with AA for AT1 was 0.63 (95% CI: 0.40–0.93). CONCLUSION: The incidence of the salt-sensitive genotypes AGT and AT1 in residents of FCs were significantly lower than in NFCs.