Fifty-year Time Trends in Blood Pressures, Body Mass Index and their Relations in a Japanese Community: The Circulatory Risk in Communities Study (CIRCS)

Nocturnal Intermittent Hypoxia and the Risk of Cardiovascular Disease among Japanese Populations: The Circulatory Risk in Communities Study (CIRCS)

AIMS

Information is limited about the influence of obstructive sleep apnea (OSA) on developing cardiovascular disease (CVD) among Asian community-dwelling populations. We examined the association between nocturnal intermittent hypoxia as a surrogate marker of OSA and the risk of CVD in a Japanese community-based cohort study.

METHODS

We used baseline surveys from 2000 to 2008 to study the cohort data of 5,313 residents from three Japanese communities who were between the ages of 40 and 74 years and initially free from ischemic heart disease and stroke. We assessed the number of 3% oxygen desaturation index (ODI) as the indicator of nocturnal intermittent hypoxia. We divided individuals into two groups depending on 3% ODI (3% ODI ≥ 5 or 3% ODI ＜5). Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for CVD according to 3% ODI. Age, sex, body mass index, alcohol, and smoking were adjusted in the multivariable models.

RESULTS

During 12.8 years of the median follow-up with 66,796 person-years, 185 cases with CVD (115 stroke and 70 coronary heart disease [CHD]) were recorded. The multivariable HRs (95% CIs) were 1.49 (1.09-2.03), 2.13 (1.08-4.22), and 1.93 (1.16-3.19) for the 3% ODI ≥ 5 group versus the 3% ODI ＜5 group of developing CVD, lacunar infarction, and CHD, respectively.

CONCLUSIONS

Nocturnal intermittent hypoxia may increase the risk of developing lacunar infarction and CHD among community-dwelling Japanese populations. However, we could not find a significant risk of developing total stroke or stroke subtypes such as intraparenchymal hemorrhage, subarachnoid hemorrhage, and total ischemic stroke.

Associations between the Combined Fat Mass Index and Fat-Free Mass Index with Carotid Intima-Media Thickness in a Japanese Population: The Tohoku Medical Megabank Community-Based Cohort Study

AIM

Although many epidemiological studies have shown that obesity assessed by body mass index is associated with carotid intima-media thickness (cIMT), few studies have evaluated fat-free mass, which is a component of body composition. We investigated the associations between the combined fat mass index (FMI) and fat-free mass index (FFMI) with cIMT.

METHODS

We conducted a cross-sectional study of 3,873 men and 9,112 women aged 20 years or older who lived in Miyagi prefecture, Japan. The FMI and FFMI were calculated as fat mass and fat-free mass divided by height squared, respectively. The indices were classified into sex-specific quartiles and were combined into 16 groups. The maximum common carotid artery was measured using high-resolution B-mode ultrasound. An analysis of covariance was used to assess associations between the combined FMI and FFMI with cIMT adjusted for age and smoking status. The linear trend test was conducted by stratifying the FMI and FFMI, scoring the categories from 1 (lowest) to 4 (highest), and entering the number as a continuous term in the regression model.

RESULTS

In multivariable models, a higher FMI was not related to higher cIMT in men and women in most FFMI subgroups. Conversely, a higher FFMI was related to higher cIMT in all FMI subgroups (p＜0.001 for linear trend).

CONCLUSIONS

FMI was not associated with cIMT in most FFMI subgroups. Conversely, FFMI was positively associated with cIMT independently of FMI.

Validation of the obesity paradox by body mass index and waist circumference in patients undergoing percutaneous coronary intervention

BACKGROUND

The paradoxical association of obesity with mortality, named the "obesity paradox", has been inconsistent, possibly due to a difference between body mass index (BMI) and central obesity, estimated by waist circumference (WC) as patterns of adiposity.

SUBJECTS/METHODS

We enrolled 8513 participants from the Kumamoto Intervention Conference Study, a multicenter registry that included consecutive patients undergoing percutaneous coronary intervention (PCI) at 18 centers between 2008 and 2017 in Japan. Patients were divided into quartiles in ascending order of the BMI or WC. The primary endpoints were all-cause mortality and cardiovascular death within a year.

RESULTS

There were 186 deaths (case fatality rate, 22.1/1000 person-years) during the follow-up period. The lowest group (1st quartile) of BMI or WC had the worst prognosis among the quartiles (1st quartile, 4.2%; 2nd quartile, 1.9%; 3rd quartile, 1.5%; 4th quartile, 1.1%; P < 0.001 (χ²) and 1st quartile, 4.1%; 2nd quartile, 2.3%; 3rd quartile, 1.2%; 4th quartile, 1.5%; P < 0.001 (χ²), respectively). Similar results were obtained for cardiovascular death. In a multivariable analysis adjusted by nine conventional factors, the lowest group (1st quartile) of BMI (hazards ratio, 2.748; 95% confidence interval [CI], 1.712-4.411) and WC (hazards ratio, 2.340; 95% CI, 1.525-3.589) were independent prognostic factors for all-cause mortality. By dividing the participants into two groups according to either the BMI or WC based on the National Cholesterol Education Program Adult Treatment Panel III and World Health Organization classification, the highest mortality was observed in the lower group. However, the C-statistic after adding BMI (quartile) to conventional factors was found to be slightly higher than BMI (two categories) and WC (two categories) (0.735 vs. 0.734).

CONCLUSIONS

The obesity paradox was observed in patients after PCI, and single-use of BMI (or WC) was sufficient to predict the prognosis of patients after PCI.

Trends for the Association between Body Mass Index and Risk of Cardiovascular Disease among the Japanese Population: The Circulatory Risk in Communities Study (CIRCS)

AIM

This study aimed to investigate whether the impact of body mass index (BMI) on the risk of cardiovascular disease (CVD) has changed among the 1960s, 1970s, 1980s, 1990s, and early 2000s in Japan.

METHODS

The study population consisted of residents in Japan aged 40-69 years who had no history of CVD. The baseline surveys have been conducted every year since 1963. We defined the first, second, third, fourth, and fifth cohorts as 1963-1969 (n=4,248), 1970-1979 (n=6,742), 1980-1989 (n=12,789), 1990-1999 (n=12,537), and 2000-2005 (n=9,140) respectively. The participants were followed up for a median of 15 years for each cohort to determine the incidence of CVD. We classified them into four categories (BMI ＜21.0, 21.0-＜23.0, 23.0-＜25.0, and ≥ 25.0 kg/m ²).

RESULTS

From 1963-1969 to 2000-2005, the prevalence of BMI ≥ 25.0 increased over time. Compared with BMI 23.0-＜25.0, the age-, sex- and community-adjusted hazard ratios (95% confidence interval [CIs]) of CVD for BMI ≥ 25.0 were 1.10 (0.77-1.57), 0.89 (0.68-1.18), 1.03 (0.85-1.26), 1.28 (1.04-1.58), and 1.36 (1.04-1.78)in the first, second, third, fourth, and fifth cohorts, respectively. The corresponding population attributable fractions were 2.0% (nonsignificant), -2.6% (nonsignificant), 0.9% (nonsignificant), 7.6%, and 10.9%. Further adjustment for systolic blood pressure and antihypertensive medication use in the fourth and fifth cohorts attenuated the associations, which may reflect that blood pressure may mediate the BMI-CVD association.

CONCLUSION

The proportion of CVD attributable to overweight/obesity has increased during the periods between 1963-1969 and 2000-2005. The significant associations between overweight/obesity and risk of CVD after the 1990s were mediated by blood pressure levels.

Changes in cause-specific mortality trends across occupations in working-age Japanese women from 1980 to 2015: a cross-sectional analysis

Background

Reducing health inequalities is an important public health challenge. Many studies have examined the widening health gap by occupational class among men, but few among women. We therefore estimated variation in absolute and relative mortality by occupational category across four leading causes of mortality—cancer, ischaemic heart disease, cerebrovascular disease, and suicide—to explore how occupational class is associated with health among working women aged 25–64 in Japan.

Methods

We conducted a repeated cross-sectional study using Poisson regression analysis on each five-yearly mortality data from 1980 to 2015, obtained from the National Vital Statistics and the Japanese Population Census.

Results

There was a decreasing trend in mortality from all cancers, ischaemic heart disease, cerebrovascular disease, and suicide among women in all occupational groups from 1980 to 2015. Agriculture workers had higher risk of mortality than professional workers for all four causes of death. The absolute difference in mortality rates for all cancers and cerebrovascular disease was higher in 2000–2015 than 1980–1995. The mortality trend among clerks and sales workers decreased after 2000, except for suicide.

Conclusions

Mortality rates from all four causes are higher among agriculture workers compared to professional workers, and attention is needed to reduce this mortality gap. Continuous monitoring of ongoing mortality trends is essential to ensure better health and wellbeing in Japan.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-022-01621-4.

Elevated Blood Pressure (≥120/80 mmHg) Is Associated with Elevated Serum Plasminogen Activator Inhibitor-1, Low Birth Weight, and Family History of Diabetes in Young Normal Weight Japanese Women

Objective: We examined whether elevated blood pressure (BP) (≥120/80 mmHg) was associated with several anthropometric, metabolic, and clinical variables, including the family history of type 2 diabetes (FHD) and low birth weight, in young normal weight Japanese women. Methods: BP, body composition, and fasting glucose, insulin, lipids, lipoproteins, apolipoproteins, and adipokines were measured in 332 young Japanese women. They received a questionnaire on birth weight and FHD. Results: The prevalence of low birth weight was 2.4% and that of positive FHD was 22.9%. Homeostasis model assessment-insulin resistance averaged <1.5 and did not differ cross-sectionally between 32 women with elevated BP and 300 women with normal BP although mean body mass index was higher in the former than in the latter (21.7 ± 2.9 kg/m² vs. 20.8 ± 2.2 kg/m², P = 0.02). Women with elevated BP had higher fat mass index (P = 0.02) and trunk fat percentage (P = 0.04). They had lower high-density lipoprotein (HDL) cholesterol and apolipoprotein A1 (both P = 0.01) while fasting triglycerides and apolipoprotein B did not differ. In addition, they had higher plasminogen activator inhibitor-1 (PAI-1) (P = 0.001). Furthermore, the prevalence of low birth weight (9.4% vs. 1.7%, P = 0.03) and positive FHD (40.6% vs. 20.0%, P = 0.01) was higher in women with elevated BP. Multivariable logistic regression analyses revealed that elevated BP was independently associated with PAI-1 [odds ratio (OR); 1.05, 95% confidence interval (CI): 1.02-1.08, P = 0.001], low birth weight (OR: 12.3, 95% CI: 2.3-67.3, P = 0.04), and FHD (OR: 3.0, 95% CI: 1.3-7.9, P = 0.01). Conclusion: Elevated BP was associated with positive FHD, low birth weight, and elevated serum PAI-1 in young normal weight Japanese women.

Effects of nocturnal light exposure on circadian rhythm and energy metabolism in healthy adults: A randomized crossover trial

Exposure to continuous light at night, including night-shift work or a nocturnal lifestyle, is emerging as a novel deleterious factor for weight gain and obesity. Here, we examined whether a single bout of bright light (BL) exposure at night affects energy metabolism via changes in circadian rhythm and nocturnal melatonin production. Ten healthy young men were randomized to a two-way crossover experimental design protocol: control (< 50 lux) and BL (approximately 10000 lux) conditions, with at least seven days of interval. The participants were exposed to each condition for 3 h (21:00-24:00) before sleep (0 lux, 00:00-07:00) in a room-type metabolic chamber. On each experimental night (21:00-07:00), energy expenditure, respiratory quotient (RQ), and substrate oxidation were measured to determine the energy metabolism. BL exposure prior to bedtime altered biological rhythms, disrupted the nocturnal decline in body temperature, and suppressed the melatonin level before sleeping, resulting in an increase in sleep latency. Indirect calorimetry data revealed that BL exposure significantly decreased the fat oxidation and increased the RQ, an indicator of the carbohydrate-to-fat oxidation ratio, throughout the whole period (light exposure and sleep). We revealed that acute BL exposure prior to bedtime exacerbated circadian rhythms and substrate oxidations, suggesting that chronic BL exposure at night may lead to obesity risk due to disturbances in circadian rhythms and macronutrient metabolism.

Risk Classification for Metabolic Syndrome and the Incidence of Cardiovascular Disease in Japan With Low Prevalence of Obesity: A Pooled Analysis of 10 Prospective Cohort Studies

Background It is uncertain whether risk classification under the nationwide program on screening and lifestyle modification for metabolic syndrome captures well high-risk individuals who could benefit from lifestyle interventions. We examined the validity of risk classification by linking the incidence of cardiovascular disease (CVD). Methods and Results Individual-level data of 29 288 Japanese individuals aged 40 to 74 years without a history of CVD from 10 prospective cohort studies were used. Metabolic syndrome was defined as the presence of high abdominal obesity and/or overweight plus risk factors such as high blood pressure, high triglyceride or low high-density lipoprotein cholesterol levels, and high blood glucose levels. The risk categories for lifestyle intervention were information supply only, motivation-support intervention, and intensive support intervention. Sex- and age-specific hazard ratios and population attributable fractions of CVD, which were also further adjusted to consider non-high density lipoprotein cholesterol levels, were estimated with reference to nonobese/overweight individuals, using Cox proportional hazard regression. Since the reference category included those with risk factors, we set a supernormal group (nonobese/overweight with no risk factor) as another reference. We documented 1023 incident CVD cases (565 men and 458 women). The adjusted CVD risk was 60% to 70% higher in men and women aged 40 to 64 years receiving an intensive support intervention, and 30% higher in women aged 65 to 74 years receiving a motivation-support intervention, compared with nonobese/overweight individuals. The population attributable fractions in men and women aged 40 to 64 years receiving an intensive support intervention were 17.7% and 6.6%, respectively, while that in women aged 65 to 74 years receiving a motivation-support intervention was 9.4%. Compared with the supernormal group, nonobese/overweight individuals with risk factors had similar hazard ratios and population attributable fractions as individuals with metabolic syndrome. Conclusions Similar CVD excess and attributable risks among individuals with metabolic syndrome components in the absence and presence of obesity/overweight imply the need for lifestyle modification in both high-risk groups.

Impact of Major Cardiovascular Risk Factors on the Incidence of Cardiovascular Disease among Overweight and Non-Overweight Individuals: The Circulatory Risk in Communities Study (CIRCS)

Aim: We aimed to examine the impact of high-risk levels of cardiovascular risk factors on the incidence of cardiovascular disease (CVD) in overweight and non-overweight individuals without treatment for the risk factors.

Methods: A total of 8,051 individuals aged 40–74 years without a history of CVD and/or without treatment for hypertension, diabetes, hyperlipidemia, and kidney disease at baseline in 1995–2000 were followed up for a median of 14.1 years. We classified the participants into three risk categories (low-, intermediate-, and high-risk groups) on the basis of individual risk factors (blood pressure, serum glucose, low-density lipoprotein cholesterol [LDL-C], and urinary protein) according to the guidelines of Japanese clinical societies. The high-risk group (systolic blood pressure ≥ 160 mmHg or diastolic blood pressure ≥ 100 mmHg, fasting serum glucose ≥ 130 mg/dL or non-fasting serum glucose ≥ 180 mg/dL, LDL-C ≥ 180 mg/dL, proteinuria ≥ 2+) needed to refer to physicians or start treatment immediately. Overweight was defined as a body mass index of ≥ 25 kg/m ² .

Results: Compared with those in the non-overweight low-risk group, the hazard ratios (HRs) (95% confidence intervals, population-attributable fractions [PAFs]) of CVD in the high-risk categories of blood pressure were 2.0 (1.4–2.9, 7.0%) in the non-overweight high-risk group and 2.9 (1.9–4.3, 6.8%) in the overweight high-risk group. The corresponding HRs (95% confidence intervals, PAFs) of serum glucose were 2.0 (1.2–3.4, 2.5%) and 2.2 (1.1–4.3, 1.5%) in the non-overweight and overweight high-risk groups, respectively. Such associations were not observed for the high-risk group of LDL-C and proteinuria.

Conclusions: The present long-term observational study implies that targeting persons with non-treated severe hypertension and diabetes is prioritized to prevent CVD regardless of overweight status.

Trends in BMI among elderly Japanese population: findings from 1973 to 2016 Japan National Health and Nutrition Survey

OBJECTIVE

To examine 44-year trends in height, weight and BMI, and the prevalence of overweight/obesity and underweight in the elderly Japanese population because Japan, the country with the longest life expectancy, has the highest ageing population.

DESIGN

Using the nationally representative cumulative data from the Japan National Health and Nutrition Survey 1973-2016, sex-specific and age-adjusted mean height, weight and BMI, and the prevalence of overweight/obesity and underweight were calculated for each year. Trend analyses were performed using the Joinpoint Regression Program. Next, changes in height, weight and BMI, and the prevalence of overweight/obesity and underweight were estimated for each age group (65-69, 70-79 and >80 years) according to the birth year groups.

SETTING

Japan.

PARTICIPANTS

Individuals aged ≥65 years with complete data on height and body weight measurements (N 94 508).

RESULTS

Trends in average height and weight increased over the four decades in both men and women. The prevalence of overweight/obesity dramatically increased and nearly tripled in men, accompanied with significantly decreased underweight prevalence. Furthermore, the increasing trend in average BMI and overweight/obesity prevalence in women reached a peak in 2002 and showed a decreasing trend thereafter, while a downward trend in underweight prevalence showed a gradual increase in women since 2003.

CONCLUSIONS

Trends in height, weight and BMI among the elderly population should continue to be closely monitored in parallel with the effects of dietary changes, energy intake and physical activity (step counts).

Associations of snoring frequency with blood pressure among the lean Japanese population: the Toon Health Study

To date, there are few studies in Asian populations on the association between snoring (a major clinical symptom of sleep apnea) and hypertension. This study aims to examine whether snoring frequency is associated with blood pressure and hypertension in the general Japanese population, after adjustment for major confounding factors. A cross-sectional study of 2021 middle-aged Japanese men and women enrolled in the Toon Health Study between 2009-2012 was conducted. Snoring frequency was assessed using a self-reported questionnaire, and was classified into four categories: never, ≤2 times/week, ≥3 times/week, and unknown. Multivariable regression coefficients for each snoring category were calculated for systolic and diastolic blood pressure, and their odds ratios (ORs) and 95% confidence intervals (95% CIs) for hypertension were calculated after adjusting for major confounding factors. The same analyses were also conducted after stratification by several major confounding factors. Multivariable-adjusted means of systolic and diastolic blood pressure among individuals who snored ≥3 times/week were 4.57 mmHg and 2.58 mmHg higher, respectively, than in individuals who never snored (p < 0.05). The multivariable-adjusted OR (95% CI) for hypertension in the group that snored ≥3 times/week was 1.79 (1.29-2.48), compared with the group that never snored. We also found a significant positive association between snoring frequency and hypertension not only in normal and overweight individuals, but also in lean individuals (body mass index ≤22.8 kg/m²). Higher snoring frequency was associated with higher blood pressure and hypertension among both lean and non-lean Japanese.

The Circulatory Risk in Communities Study (CIRCS): A Long-Term Epidemiological Study for Lifestyle-Related Disease Among Japanese Men and Women Living in Communities

The Circulatory Risk in Communities Study (CIRCS) is an ongoing community-based epidemiological study of lifestyle-related disease involving dynamic prospective cohorts of approximately 12,000 adults from five communities of Japan: Ikawa, Ishizawa and Kita-Utetsu (Akita Prefecture), Minami-Takayasu (Osaka Prefecture), Noichi (Kochi Prefecture), and Kyowa (Ibaraki Prefecture). One of the most notable features of CIRCS is that it is not only an observational cohort study to identify risk factors for cardiovascular diseases (CVD), such as stroke, coronary heart disease, and sudden cardiac death, but it also involves prevention programs for CVD. Using basic, clinical, epidemiological, and statistical techniques, CIRCS has clarified characteristics of CVD and the related risk factors to develop specific methodologies towards CVD prevention in Japanese middle-aged or older adults for more than half a century.

Lack of Association between Hepatitis C Virus core Gene Variation 70/91aa and Insulin Resistance

The role of hepatitis C virus (HCV) in insulin resistance (IR) is not fully understood. The aim of this study was to determine the impact of amino acid (aa) substitutions in the core region of HCV according to IR and to identify clinical and laboratory associations. Ninety-two treatment-naive HCV patients were recruited to determine laboratory data and blood cell count. IR was determined using Homeostasis Model Assessment (HOMA) index where IR was defined as HOMA ≥2. HCV RNA load and genotype were determined by Abbott Real time HCV. HCV core region was determined by direct nucleotide sequencing. Bivariate analysis was conducted using HOMA IR ≥2 as a dependent factor. IR prevalence was 43.5% (n = 40), vitamin D sufficiency was found in 76.1% (n = 70) and 72.8% (n = 67) had advanced liver fibrosis. In the bivariate analyses, elevated values of γGT (p = 0.024) and fibrosis staging (p = 0.004) were associated with IR, but IR was not related to core mutations. The presence of glutamine in position 70 was associated with low vitamin D concentration (p = 0.005). In the multivariate analysis, no variable was independently associated with HOMA-IR. In conclusion, lack of association between IR and HCV core mutations in positions 70 and 91 suggests that genetic variability of this region has little impact on IR.