Home blood pressure measurement days and changes in urinary sodium-to-potassium ratio, estimated salt and potassium intakes and blood pressure: 1-year prospective study.

OBJECTIVE: Current international guidelines recommend home blood pressure (BP) measurement and low sodium and high potassium intakes for the management of hypertension. We hypothesized that increased home BP measurement may result in more effective management of sodium and potassium intakes and BP. METHODS: We examined associations of home BP measurement days with changes in the urinary sodium-to-potassium (Na/K) ratio, estimated salt and potassium intakes and BP. We included 209 healthy participants (mean age, 55.9 years; 56.5% women) from a prospective cohort study. We examined 1-year data on self-measured home BP and spot urine samples. RESULTS: Median (interquartile range) days of home BP measurement was 324 (225-358) over 1-year. Baseline mean (SD) Na/K ratio, salt and potassium intakes, morning and evening SBP, and morning and evening DBP were 3.8 (2.3), 8.5 (1.9) g/day, 1833.5 (416.5) mg/day, 120.4 (14.0) mmHg, 118.2 (14.2) mmHg, 79.2 (10.1) mmHg, and 76.2 (10.1) mmHg, respectively. In multivariable-adjusted linear regression , ß (standard error) per 10 days increase in number of home BP measurement were -0.031 (0.017) for Na/K ratio, -0.036 (0.015) for salt intake, -1.357 (2.797) for potassium intake, -0.178 (0.064) for morning SBP, -0.079 (0.041) for morning DBP, -0.109 (0.067) for evening SBP and -0.099 (0.045) for evening DBP. Additionally, relationships persisted for men and women, but changes in salt intake were more pronounced among participants taking antihypertensive medication (interaction P = 0.002). CONCLUSION: Continuous measurement of home BP may lead not only to self-monitoring of BP, but also to declines in salt intakes and some BP indices.

Associations of indoor and outdoor temperatures and their difference with home blood pressure: The Masuda Study.

Ambient temperature and blood pressure (BP) are closely related; however, few studies have examined the association of out-of-office BP with indoor or outdoor temperature. The effect of the difference between indoor and outdoor temperatures on BP also remains unknown. Therefore, this study aimed to investigate the association of indoor and outdoor temperatures and their difference with home BP. We studied healthy 352 participants (mean age, 49.8 years; 46.0% women) from a population-based cohort using 2-year data on temperature and self-measured home BP. We measured home BP and indoor temperature at the same time in the morning and evening every day. Outdoor temperature during the same period was based on national data. We observed 82,900 home BP measurements in the morning and 66,420 in the evening. In the mixed-effects model adjusted for age, sex, and possible confounders, indoor temperature was inversely associated with systolic and diastolic BP in the morning and evening. A 1 °C increase in indoor temperature reduced systolic and diastolic BP by 0.37 and 0.22 mmHg, respectively, in the morning and by 0.45 and 0.30 mmHg, respectively, in the evening (all P-values<0.001). The magnitude of associations was stronger for indoor than outdoor temperature. Similarly, a 1 °C increase in indoor temperature above outdoor temperature decreased systolic and diastolic BP by 0.33 and 0.12 mmHg, respectively, in the morning and by 0.45 and 0.26 mmHg, respectively, in the evening independent of outdoor temperature (all P-values <0.001). In conclusion, controlling indoor temperature is important to stabilize home BP levels.

Reproducibility and validity of food group intake in a short food frequency questionnaire for the middle-aged Japanese population.

PURPOSE: The purpose of this study was to evaluate the reproducibility and validity of a short food frequency questionnaire (FFQ) for food group intake in Japan, the reproducibility and partial validity of which were previously confirmed for nutrients. METHODS: A total of 288 middle-aged healthy volunteers from 11 different areas of Japan provided nonconsecutive 3-day weighed dietary records (DRs) at 3-month intervals over four seasons. We evaluated reproducibility based on the first (FFQ1) and second (FFQ2) questionnaires and their validity against the DRs by comparing the intake of 20 food groups. Spearman's rank correlation coefficients (SRs) were calculated between energy-adjusted intake from the FFQs and that from the DRs. RESULTS: The intake of 20 food groups estimated from the two FFQs was mostly equivalent. The median energy-adjusted SRs between the FFQ1 and FFQ2 were 0.61 (range 0.38-0.86) for men and 0.66 (0.45-0.84) for women. For validity, the median de-attenuated SRs between DRs and the FFQ1 were 0.51 (0.17-0.76) for men and 0.47 (0.23-0.77) for women. Compared with the DRs, the proportion of cross-classification into exact plus adjacent quintiles with the FFQ1 ranged from 58 to 86% in men and from 57 to 86% in women. According to the robust Z scores and the Bland-Altman plot graphs, the underestimation errors in the FFQ1 tended to be greater in individuals with high mean levels of consumption for meat for men and for other vegetables for both men and women. CONCLUSION: The FFQ demonstrated high reproducibility and reasonable validity for food group intake. This questionnaire is short and remains appropriate for identifying associations between diet and health/disease among adults in Japan.

Interactions between inflammatory gene polymorphisms and HTLV-I infection for total death, incidence of cancer, and atherosclerosis-related diseases among the Japanese population.

BACKGROUND: An increased risk of total death owing to human T-lymphotropic virus type-I (HTLV-I) infection has been reported. However, its etiology and protective factors are unclear. Various studies reported fluctuations in immune-inflammatory status among HTLV-I carriers. We conducted a matched cohort study among the general population in an HTLV-I-endemic region of Japan to investigate the interaction between inflammatory gene polymorphisms and HTLV-I infection for total death, incidence of cancer, and atherosclerosis-related diseases. METHOD: We selected 2180 sub-cohort subjects aged 35-69 years from the cohort population, after matching for age, sex, and region with HTLV-I seropositives. They were followed up for a maximum of 10 years. Inflammatory gene polymorphisms were selected from TNF-α, IL-10, and NF-κB1. A Cox proportional hazard model was used to estimate the hazard ratio (HR) and the interaction between gene polymorphisms and HTLV-I for risk of total death and incidence of cancer and atherosclerosis-related diseases. RESULTS: HTLV-I seropositivity rate was 6.4% in the cohort population. The interaction between TNF-α 1031T/C and HTLV-I for atherosclerosis-related disease incidence was statistically significant (p = 0.020). No significant interaction was observed between IL-10 819T/C or NF-κB1 94ATTG ins/del and HTLV-I. An increased HR for total death was observed in the Amami island region, after adjustment of various factors with gene polymorphisms (HR 3.03; 95% confidence interval, 1.18-7.77). CONCLUSION: The present study found the interaction between TNF-α 1031T/C and HTLV-I to be a risk factor for atherosclerosis-related disease. Further follow-up is warranted to investigate protective factors against developing diseases among susceptible HTLV-I carriers.

Comparison of weighed food record procedures for the reference methods in two validation studies of food frequency questionnaires.

BACKGROUND: Although open-ended dietary assessment methods, such as weighed food records (WFRs), are generally considered to be comparable, differences between procedures may influence outcome when WFRs are conducted independently. In this paper, we assess the procedures of WFRs in two studies to describe their dietary assessment procedures and compare the subsequent outcomes. METHODS: WFRs of 12 days (3 days for four seasons) were conducted as reference methods for intake data, in accordance with the study protocol, among a subsample of participants of two large cohort studies. We compared the WFR procedures descriptively. We also compared some dietary intake variables, such as the frequency of foods and dishes and contributing foods, to determine whether there were differences in the portion size distribution and intra- and inter-individual variation in nutrient intakes caused by the difference in procedures. RESULTS: General procedures of the dietary records were conducted in accordance with the National Health and Nutrition Survey and were the same for both studies. Differences were seen in 1) selection of multiple days (non-consecutive days versus consecutive days); and 2) survey sheet recording method (individual versus family participation). However, the foods contributing to intake of energy and selected nutrients, the portion size distribution, and intra- and inter-individual variation in nutrient intakes were similar between the two studies. CONCLUSION: Our comparison of WFR procedures in two independent studies revealed several differences. Notwithstanding these procedural differences, however, the subsequent outcomes were similar.

Validity of a food frequency questionnaire in a population with high alcohol consumption in Japan.

BACKGROUND AND OBJECTIVES: Alcohol consumption has a relatively large impact on energy intake in drinkers, and several studies reported different dietary habits from non-drinkers. However, few studies have investigated the influence of alcohol consumption on the validity of the Food Frequency Questionnaire (FFQ). To investigate its influence, we conducted a validity test in a population with high alcohol consumption. METHODS AND STUDY DESIGN: The study subjects were 66 residents living on an island in the south-western part of Japan. We conducted the FFQ and 12-day-weighed dietary records (12d-WDRs) in each 3 day of each 4 season. We calculated Pearson correlation coefficients (CCs) and agreement rates according to quartile classification after adjusting for energy. RESULTS: The intake energy (kcal) estimated from 12d-WDRs and FFQ was 1,641 and 1,534 in women, and 2,093 and 1,979 in men, respectively. The cumulative percentage contribution of the alcohol energy was 6.7% in men. De-attenuated, log-transformed Pearson's median CCs between the nutrients quantified with the 12d-WDRs and FFQ were 0.51 in women and 0.38 in men. The CCs for carbohydrate and saturated fatty acids intake of men were lower than those in the previous Tokai study using the same FFQ. The findings in agreement rates were consistent with the Tokai study. CONCLUSION: This study suggested that the FFQ can be used for epidemiological studies using categorical comparisons in this population, although the underestimation of carbohydrates and other nutrients in the FFQ should be taken into consideration.

Positive Association of Plasma Homocysteine Levels with Cardio-Ankle Vascular Index in a Prospective Study of Japanese Men from the General Population.

AIM: Observational studies have reported that elevated homocysteine (Hcy) levels are associated with the risk of cardiovascular disease (CVD). However, interventions that lower Hcy do not provide a corresponding risk reduction. Therefore, the causal role of Hcy in CVD remains unclear. This 5-year prospective study investigated the associations of Hcy levels, folate intake, and host factors with arterial stiffness among the general Japanese population. METHODS: We prospectively recruited 658 participants (40-69 years old) from the general population during regular health checkup examinations. Arterial stiffness was evaluated using the cardio-ankle vascular index (CAVI) at baseline and the 5-year follow-up. Folate intake was estimated using a structured questionnaire. Genotyping was used to evaluate the MTHFR C677T and MS A2756G gene polymorphisms. Ultrafast liquid chromatography was used to measure total plasma Hcy levels. Association between these variables and CAVI values was evaluated using general linear regression and logistic regression models that were adjusted for atherosclerosis-related factors. RESULTS: Men had higher Hcy levels and CAVI values and lower folate intake than women (all, p＜0.001). At baseline, Hcy, folate intake, and the two genotypes were not associated with CAVI values for both sexes. Among men, Hcy levels were positively associated with CAVI values at the 5-year follow-up (p=0.033). Folate intake and the two genotypes were not associated with the 5-year CAVI values. CONCLUSION: Plasma Hcy may be involved in arterial stiffness progression, as monitored using CAVI, among men.

Variant of the clock circadian regulator (CLOCK) gene and related haplotypes are associated with the prevalence of type 2 diabetes in the Japanese population.

BACKGROUND: Circadian rhythm disruptions can cause various health disorders. The present study evaluated associations between single nucleotide polymorphisms in the core circadian gene clock circadian regulator (CLOCK) and the prevalence of type 2 diabetes (T2D) in the Japanese population. METHODS: Cross-sectional data were analyzed from 2485 subjects (1243 men, 1242 women; age 35-69 years) enrolled in the baseline surveys of the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study. Associations between three CLOCK gene polymorphisms (rs1801260, rs3736544, and rs4864548) and the prevalence of obesity (body mass index [BMI] ≥25 kg/m(2) ), overweight (BMI ≥23 kg/m(2) ), and T2D were evaluated by logistic regression analyses; haplotype analysis and stratified analyses for the prevalence of diabetes were also conducted. RESULTS: Compared with those who were homozygous for the respective major alleles, subjects with the rs1801260 minor allele C had a significantly higher odds ratio (1.5; 95% confidence interval 1.1-2.1) for the prevalence of diabetes after adjustment for potential confounding factors, including BMI. When stratified by overweight, the associations between rs1801260 and the prevalence of diabetes were marked and significant in non-overweight subjects, but not in overweight subjects. The TGA (rs1801260-rs3736544-rs4864548) haplotype was associated with a lower prevalence of diabetes, whereas the CGG haplotype was associated with a higher prevalence of diabetes. CONCLUSIONS: Variant of the CLOCK gene and related haplotypes are associated with the prevalence of T2D in the Japanese population, in which obesity is less common, and the association between CLOCK gene variant at rs1801260 and the prevalence of diabetes is enhanced in normal-weight subjects.

GCK, GCKR polymorphisms and risk of chronic kidney disease in Japanese individuals: data from the J-MICC Study.

BACKGROUND: Chronic kidney disease (CKD) is well known as a strong risk factor for both of end-stage renal disease and cardiovascular disease. To clarify the association of glucokinase and glucokinase regulatory protein (GCKR) polymorphisms with the risk of CKD in Japan, we examined this association among Japanese individuals using cross-sectional data. METHODS: The subjects for this analysis were 3,314 consecutively selected participants from the Japan Multi-Institutional Collaborative Cohort Study. Age- and sex- adjusted odds ratios (aORs) of CKD stages 3-5 were calculated for each genotype by logistic regression and the effects of genotype on estimated glomerular filtration rate were evaluated by linear regression. Gene-environment interaction was also investigated based on questionnaire information. RESULTS: When subjects with GCKR rs780094 G/A and G/G, or GCKR rs1260326 T/C and C/C were combined together and compared with the references (GCKR rs780094 A/A or GCKR rs1260326 T/T), the aORs were 0.84 (0.69-1.02) or 0.81 (0.67-0.99) (p = 0.075 or 0.037), respectively. A significant OR for interaction between GCKR rs1260326 T/T and current smoking (OR = 1.79, p = 0.041) was also observed. CONCLUSION: The present study suggests a possible association of the T/T genotype of GCKR rs1260326 polymorphism with elevated risk of CKD and its interaction with current smoking, which may support the possibility of performing risk evaluation and prevention of this potentially life-threatening disease based on genetic traits in the near future.

Association of inflammatory gene polymorphisms and conventional risk factors with arterial stiffness by age.

BACKGROUND: Inflammatory gene polymorphisms are potentially associated with atherosclerosis risk, but their age-related effects are unclear. To investigate the age-related effects of inflammatory gene polymorphisms on arterial stiffness, we conducted cross-sectional and 5-year follow-up studies using the cardio-ankle vascular index (CAVI) as a surrogate marker of arterial stiffness. METHODS: We recruited 1850 adults aged 34 to 69 years from the Japanese general population. Inflammatory gene polymorphisms were selected from NF-kB1, CD14, IL-6, IL-10, MCP-1, ICAM-1, and TNF-α. Associations of CAVI with genetic and conventional risk factors were estimated by sex and age group (34-49, 50-59, and 60-69 years) using a general linear model. The association with 5-year change in CAVI was examined longitudinally. RESULTS: Glucose intolerance was associated with high CAVI among women in all age groups, while hypertension was associated with high CAVI among participants in all age groups, except younger women. Mean CAVI for the CD14 CC genotype was lower than those for the TT and CT genotypes (P for trend = 0.005), while the CD14 polymorphism was associated with CAVI only among men aged 34 to 49 years (P = 0.006). No association of the other 6 polymorphisms with CAVI was observed. No association with 5-year change in CAVI was apparent. CONCLUSIONS: Inflammatory gene polymorphisms were not associated with arterial stiffness. To confirm these results, further large-scale prospective studies are warranted.

Genome-wide association study of genetic factors related to confectionery intake: potential roles of the ADIPOQ gene.

OBJECTIVE: The excessive consumption of confectionery might have adverse effects on human health. To screen genetic factors associated with confectionery-intake frequency, a genome-wide association study (GWAS) in Japan was conducted. DESIGN AND METHODS: For the discovery phase (stage 1), we conducted a GWAS of 939 noncancer patients in a cancer hospital. Additive models were used to test associations between genotypes of approximately 500,000 single-nucleotide polymorphisms (SNPs) and the confectionery-intake score (based on intake frequency). We followed-up association signals with P < 1 × 10(-5) and minor allele frequency >0.01 in stage 1 by genotyping the SNPs of 4,491 participants in a cross-sectional study within a cohort (replication phase [stage 2]). RESULTS: We identified 12 SNPs in stage 1 that were potentially related to confectionery intake. In stage 2, this association was replicated for one SNP (rs822396; P = 0.049 for stage 2 and 4.2 × 10(-5) for stage 1+2) in intron 1 of the ADIPOQ gene, which encodes the adipokine adiponectin. CONCLUSIONS: Given the biological plausibility and previous relevant findings, the association of an SNP in the ADIPOQ gene with a preference for confectionery is worthy of follow-up and provides a good working hypothesis for experimental testing.