Total protein intake and subsequent risk of chronic kidney disease: the Circulatory Risk in Communities Study.

BACKGROUND: Whether dietary protein intake worsens renal function in the general population has been discussed but not yet determined. We aimed to examine the longitudinal association between dietary protein intake and risk of incident chronic kidney disease (CKD). METHODS: We conducted a 12-year follow-up study with 3,277 Japanese adults (1,150 men and 2,127 women) aged 40-74 years, initially free from CKD, who participated in cardiovascular risk surveys from two Japanese communities under the Circulatory Risk in Communities Study. The development of CKD was defined by the estimated glomerular filtration rate (eGFR) during the follow-up period. Protein intake was measured at baseline by using the brief-type self-administered diet history questionnaire. We estimated sex-, age-, community- and multivariate-adjusted hazard ratios (HR) for incident CKD were calculated using the Cox proportional hazards regression models according to quartiles of percentage of energy (%energy) from protein intake. RESULTS: During 26,422 person-years of follow-up, 300 participants developed CKD (137 men and 163 women). The sex-, age-, and community-adjusted HR (95% confidence interval, CI) for the highest (≥16.9%energy) versus lowest (≤13.4%energy) quartiles of total protein intake was 0.66 (0.48-0.90), p for trend = 0.007. The multivariable HR (95%CI) was 0.72 (0.52-0.99), p for trend = 0.016 after further adjustment for body mass index, smoking status, alcohol drinking status, diastolic blood pressure, antihypertensive medication use, diabetes mellitus, serum total cholesterol levels, cholesterol-lowering medication use, total energy intake, and baseline eGFR. The association did not vary by sex, age, and baseline eGFR. When examining animal and vegetable protein intake separately, the respective multivariable HRs (95%CIs) were 0.77 (0.56-1.08), p for trend = 0.036, and 1.24 (0.89-1.75), p for trend = 0.270. CONCLUSIONS: Higher protein intake, more specifically animal protein intake was associated with a lower risk of CKD.

Circadian Clock Gene Polymorphisms and Sleep-Onset Problems in a Population-Based Cohort Study: The Yamagata Study.

A number of genome-wide association studies have investigated sleep phenotypes and disorders in humans. However, the contribution of genetic variation to sleep problems in Japanese populations has remained unclear. Sleep-onset problems are the most common symptom of insomnia. Here, we examined the relationship between single nucleotide polymorphisms (SNPs) of BMAL1 (ARNTL1), CLOCK, CRY1, CRY2, and PER2, which are genes involved in the clock mechanism, and sleep-onset problems in a Japanese general population. This study included 1,397 subjects aged ≥ 40 years who participated in an annual health check-up in Yamagata Prefecture. A total of 80 SNPs of 5 circadian clock genes were analyzed. Multivariate logistic regression analyses identified variant rs11113179 in CRY1 and variants rs1026071 and rs1562438 in BMAL1 as genetic risk factors for sleep induction disorder. These findings suggest that CRY1 and BMAL1 polymorphisms are related to sleep-onset problems in a Japanese general population. However, none of the SNPs remained significant at a stringent level of multiple correction.

Dietary Exposure of the Japanese General Population to Elements: Total Diet Study 2013-2018.

Some countries have conducted a total diet study (TDS) focused on the estimation of specific trace elements. Although some results of a Japanese TDS examining trace elements were published, there have been no reports of a nationwide TDS across Japan over a multi-year period to estimate the level of exposure to multiple elements. In the present study, a TDS using a market basket approach was performed to estimate the dietary exposure levels of the general population of Japan to 15 elements, including aluminum (Al), total arsenic (tAs), boron (B), barium (Ba), cadmium (Cd), cobalt (Co), chromium (Cr), total mercury (THg), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), selenium (Se), tin (Sn), and uranium (U). Samples prepared in eight regions across Japan over a 6-year period were analyzed using validated methods. The robust mean exposure estimates for Al, tAs, B, Ba, Cd, Co, Cr, THg, Mo, Ni, Pb, Sb, Se, Sn, and U were 48, 4.2, 29, 8.6, 0.35, 0.17, 0.49, 0.14, 4.2, 2.8, 0.15, 0.022, 1.8, 0.10, and 0.021 µg/kg body weight/day, respectively. Although the variability in exposure estimates varied greatly from element to element, the relative standard deviations calculated from the robust means and robust standard deviations were ≤ 50% for all elements except Sn. Compared against the health-based guidance values, none of the robust and precise estimates obtained for the target elements would be associated with urgent health risk concern. In addition, the estimated exposure levels were generally in agreement with previously reported estimates, indicating that health risks associated with exposure to these elements have not changed markedly nationwide in Japan in recent years.

Recent status of self-measured home blood pressure in the Japanese general population: a modern database on self-measured home blood pressure (MDAS).

Despite the clinical usefulness of self-measured home blood pressure (BP), reports on the characteristics of home BP have not been sufficient and have varied due to the measurement conditions in each study. We constructed a database on self-measured home BP, which included five Japanese general populations as subdivided aggregate data that were clustered and meta-analyzed according to sex, age category, and antihypertensive drug treatment at baseline (treated and untreated). The self-measured home BPs were collected after a few minutes of rest in a sitting position: (1) the morning home BP was measured within 1 h of waking, after urination, before breakfast, and before taking antihypertensive medication (if any); and (2) the evening home BP was measured just before going to bed. The pulse rate was simultaneously measured. Eligible data from 2000 onward were obtained. The morning BP was significantly higher in treated participants than in untreated people of the same age category, and the BP difference was more marked in women. Among untreated residents, home systolic/diastolic BPs measured in the morning were higher than those measured in the evening; the differences were 5.7/5.0 mmHg in women (ranges across the cohorts, 5.3-6.8/4.7-5.4 mmHg) and 7.3/7.7 mmHg in men (ranges, 6.4-8.5/7.0-8.7 mmHg). In contrast, the home pulse rate in women and men was 2.4 (range, 1.5-3.7) and 5.6 (range, 4.6-6.6) beats per minute, respectively, higher in the evening than in the morning. We demonstrated the current status of home BP and home pulse rate in relation to sex, age, and antihypertensive treatment status in the Japanese general population. The approach by which fine-clustered aggregate statistics were collected and integrated could address practical issues raised in epidemiological research settings.

Frequency of forest walking is not associated with prevalence of hypertension based on cross-sectional studies of a general Japanese population: a reconfirmation by the J-MICC Daiko Study.

Forest walking or Shinrin-yoku is a health promotion activity in Japan. Although some studies have reported the acute effects of walking a few hours in forested areas in reducing blood pressure level compared to other environments, studies investigating whether successive walking has long-term effects in lowering blood pressure levels or lowering prevalence of hypertension are rare. This study aimed to reconfirm the presence or absence of an association between the frequency of forest walking and prevalence of hypertension in a Japanese population. This J-MICC Daiko Study was conducted targeting residents in Nagoya City. A total of 5,109 participants (1,452 men and 3,657 women; age, mean ± standard deviation: 52.5 ± 10.3 years) were included in the analysis. Age-adjusted blood pressure level by frequency of forest walking was not significant. After adjusting for age and lifestyle, the adjusted odds ratios (aORs) of the most frequent group (n=88, 1.7%; once a week or more group) relative to the less than once a month group (n=4,558, 89.2%) for prevalence of hypertension were not also significant [0.80 (95% CI: 0.40-1.62) for men and 1.48 (95% CI: 0.73-3.00) for women]. This study reconfirmed that either lowering blood pressure level or lowering the prevalence of hypertension is not associated with frequency of forest walking, similar to the results of our previous J-MICC Shizuoka Study. Given that these two studies were cross-sectional studies, cohort studies investigating the causal relationship are required to evaluate the effect of frequent forest walking on the prevention of hypertension.

Gender Differences in Lifestyle Factors Associated with Metabolic Syndrome and Preliminary Metabolic Syndrome in the General Population: The Watari Study.

Objective In Japan, metabolic syndrome (MetS) and preliminary metabolic syndrome (preMetS) are more prevalent in men; however, it remains unclear whether the relationship between these metabolic disorders and lifestyle factors is similar between genders. Methods We examined waist circumference, blood pressure, fasting blood, and various lifestyle factors in 3,166 individuals aged from 30-79 years of age from the Japanese general population. MetS was diagnosed on the basis of central obesity - assessed by waist circumference - plus two or more of the following cardio-metabolic risks according to Japanese criteria: high blood pressure, hyperglycemia, and lipid abnormality. Central obesity plus one of the risks was defined as preMetS. Results Men had a significantly higher prevalence of MetS (23.3% vs. 8.7%, p<0.001) and preMetS (21.2% vs. 10.2%, p<0.001) than women. An age-adjusted logistic regression analysis revealed that heavy drinkers were associated with an increased probability of MetS (odds ratio, 1.91: 95% confidence interval, 1.29-2.83) and preMetS (1.69: 1.11-2.58); fast eaters were also related to preMetS (1.83: 1.33-2.55) and MetS (1.55: 1.12-2.15) in men. Lacking regular exercise was significantly associated with preMetS (1.38: 1.03-1.85), but not MetS. In women, preMetS was significantly associated with fast eaters and lacking regular exercise (1.44: 1.01-2.07 and 1.41: 1.02-1.96, respectively); a stepwise increase in each odds ratio (2.02: 1.40-2.91 and 1.47: 1.03-2.09, respectively) was also observed for MetS. Conclusion The relationships between lifestyle factors and MetS or preMetS differed between men and women, which suggests the need for gender-specific lifestyle modification to effectively prevent MetS.