Taichiro Tanaka

A simple method to estimate populational 24-h urinary sodium and potassium excretion using a casual urine specimen

In order to estimate the salt and potassium intake in a population and to compare their annual trends, we developed a simple method to estimate population mean levels of 24-h urinary sodium (24HUNaV) and potassium (24HUKV) excretion from spot urine specimens collected at any time. Using 591 Japanese data items from the INTERSALT study as a gold standard, we developed formulas to estimate 24-h urinary creatinine (24HUCrV), 24HUNaV and 24HUKV using both spot and 24-h urine collection samples. To examine the accuracy of the formulas, we applied these equations to 513 external manual workers. The obtained formulas were as follows: (1) PRCr (mg/day) = −2.04 × age + 14.89 × weight (kg) + 16.14 × height (cm) − 2244.45; (2) estimated 24HUNaV (mEq/day) = 21.98 × XNa0.392; (3) estimated 24HUKV (mEq/day) = 7.59 × XK0.431; where PRCr = predicted value of 24HUCr, SUNa = Na concentration in the spot voiding urine, SUK = K concentration in the spot voiding urine, SUCr = creatinine concentration in the spot voiding urine, XNa (or XK) = SUNa (or SUK)/SUCr × PRCr. In the external group, there was a significant but small difference between the estimated and measured values in sodium (24.0 mmol/day) and potassium (3.8 mmol/day) excretion. In every quintile divided by the estimated 24HUNaV or 24HUKV, the measured values were parallel to the estimated values. In conclusion, although this method is not suitable for estimating individual Na and K excretion, these formulas are considered useful for estimating population mean levels of 24-h Na and K excretion, and are available for comparing different populations, as well as indicating annual trends of a particular population.

Relation between sleep quality and quantity, quality of life, and risk of developing diabetes in healthy workers in Japan: The High-risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study

BackgroundThe effect of sleep on the risk of developing diabetes has not been explored in an Asian population. The objective of this study is to investigate the effect of self-reported sleep duration and sleep quality on the risk of developing diabetes in a prospective cohort in Japan.MethodsData were analyzed from the cohort of participants in a High-risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP), conducted in Japan from the year 1999 until 2004. A Cox proportional hazard model was used to evaluate the association between sleep duration or sleep quality and the risk of diabetes.ResultsOf 6509 participants (26.1% of women, 19–69 years of age), a total of 230 type 2 diabetes cases were reported over a median 4.2 years of follow-up. For participants who often experienced difficulty in initiating sleep, the multivariate-adjusted hazard ratios for diabetes were 1.42 (95%CI, 1.05–1.91) in participants with a medium frequency of difficulty initiating sleep, and 1.61 (95%CI, 1.00–2.58) for those with a high frequency, with a statistically significant linear trend. Significant association was not observed in the association between difficulty of maintaining sleep or duration of sleep, and risk of diabetes.ConclusionMedium and high frequencies of difficulty initiating sleep, but not difficulty in maintaining sleep or in sleep duration, are associated with higher risks of diabetes in relatively healthy Asian workers, even after adjusting for a large number of possible further factors.

Is Maternal Smoking during Early Pregnancy a Risk Factor for All Low Birth Weight Infants

Background Low birth weight (LBW) infants do not form a homogeneous group; LBW can be caused by prematurity or poor fetal growth manifesting as small for gestational age (SGA) infants or intrauterine growth retardation. We aimed to clarify the relationship of maternal smoking with both SGA and preterm LBW infants. Methods The study population comprised pregnant women who registered at the Koshu City between January 1, 1995, and December 31, 2000, and their children. We performed multivariate analyses using multiple logistic regression models to clarify the relationship of maternal smoking during pregnancy with the SGA outcome and preterm birth in LBW infants. Results In this study period, 1,329 pregnant women responded to questionnaires, and infant data were collected from 1,100 mothers (follow-up rate: 82.8%). The number of LBW infants was 81 (7.4%). In this cohort, maternal smoking during early pregnancy was associated with LBW and the SGA outcome. Maternal smoking during early pregnancy was a risk factor for LBW with SGA outcome and for LBW with full-term birth. However, it was not a risk factor for LBW with appropriate weight for gestational age (AGA) and LBW with preterm birth. Conclusion These results suggested that LBW with AGA and LBW with preterm birth were associated with other risk factors that were not considered in this study, such as periodontal disease. For the prevention of LBW, not only abstinence from smoking during pregnancy but also other methods such as establishing a clinical setting should be adopted.

A Prospective Study of Passive Smoking and Risk of Diabetes in a Cohort of Workers: The High-Risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) study

OBJECTIVE—We investigated the impact of active smoking and exposure to passive smoke on the risk of developing diabetes. RESEARCH DESIGN AND METHODS—Data were analyzed from a cohort of participants in the High-Risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP) conducted in Japan from 1999 to 2004. Active and passive smoking status in the workplace was evaluated at baseline. RESULTS—Of 6,498 participants (20.9% women), a total of 229 diabetes cases were reported over a median 3.4 years of follow-up. In the workplace, compared with zero-exposure subjects, the multivariable-adjusted hazard ratios of developing diabetes were 1.81 (95% CI 1.06–3.08, P = 0.028) for present passive subjects and 1.99 (1.29–3.04, P = 0.002) for present active smokers. CONCLUSIONS—In this cohort, exposure to passive smoke in the workplace was associated with an increased risk of diabetes after adjustment for a large number of possible confounders.

Specific alcoholic beverage and blood pressure in a middle-aged Japanese population: The High-Risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study

The purpose of this study was to clarify the effects of popular Japanese alcoholic beverages on blood pressure. We performed a cross-sectional study on 4335 Japanese male workers using baseline data from an intervention study. We defined six groups according to the type of alcoholic beverage that provided two-thirds of the subjects total alcohol consumption: beer, sake (rice wine), shochu (traditional Japanese spirits), whiskey, wine and others. The partial regression coefficients of daily alcohol intake (1 drink=11.5 g of ethanol) to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 0.87(P<0.001, standard error (s.e.)=0.09) and 0.77(P<0.001, s.e.=0.06), respectively. A comparison among the types of alcoholic beverages mainly consumed revealed significant differences in SBP and DBP. Both SBP and DBP were highest in the shochu group. However, an analysis of covariance adjusting for total alcohol consumption resulted in the disappearance of these differences. Although after adjustment for total alcohol consumption, the shochu group exhibited a significant positive association with ‘high-normal blood pressure or greater’ (odds ratio 1.43, 95% confidence interval 1.06–1.95) compared with the beer group, this significant relation disappeared after adjusting for the body mass index (BMI), urinary sodium and potassium excretion. The pressor effect, per se, of popular Japanese alcoholic beverages on blood pressure may not be different among the types of alcoholic beverages after adjusting for other lifestyle factors.

Confirmatory factor analysis of the Child Feeding Questionnaire (CFQ) in Japanese elementary school children.

The validity of the Child Feeding Questionnaire (CFQ), one of the measures used to assess parental child feeding practices and attitudes, has been confirmed in American populations. We used confirmatory factor analysis to test the validity and factor structure of the translated version of the CFQ among parents of Japanese elementary school children. The structural equation modelling software Linear Structural Relationships (LISREL) was applied to explore the validity of the translated CFQ to examine child feeding behaviours and attitudes in a sample of 920 parents of Japanese elementary schoolchildren from schools in Koshu City in Yamanashi prefecture (grades 4-6), Japan. The confirmatory factor analysis suggested that after dropping the items with a low factor loading and adding three error covariances between items, the 7-factor model displayed acceptable fit and most items loaded as expected. Of the 24 direct factor-item correlations, 22 were greater than 0.50. Our study confirmed the validity of the translated CFQ to assess child feeding practices and attitudes among parents of elementary schoolchildren brought up in a Japanese eating culture.

The Association between Maternal Smoking during Pregnancy and Childhood Obesity Persists to the Age of 9-10 Years

Background We previously reported that a number of factors related to maternal lifestyle during early pregnancy, including smoking, are associated with childhood obesity at 5 years of age. In the present study, we investigated whether the association with maternal smoking persisted to the age of 9–10 years. Methods The study population comprised children born between April 1, 1991 and March 31, 1999, and their mothers. The dependent variables—childhood overweight and obesity at 5 and 9–10 years of age—were defined according to internationally acknowledged cut-off values. Maternal smoking during early pregnancy was used as the independent variable. Results Mothers who completed a specifically designed questionnaire gave birth to a total of 1644 infants during the study period. Anthropometric data were collected from 1302 of these children during medical checkups at 9–10 years of age (follow-up rate: 79.2%). Maternal smoking during early pregnancy was associated with obesity in 9- to 10-year-old children (adjusted odds ratio, 1.91; 95% confidence interval, 1.03–3.53). However, the point estimates at the age of 9–10 years were considerably lower than those at the age of 5 years. Conclusions Our results suggest that fetal environment, including exposure to maternal smoking, continues to be associated with childhood obesity at the age of 9–10 years.

The high-risk and population strategy for occupational health promotion (HIPOP-OHP) study: study design and cardiovascular risk factors at the baseline survey.

In order to establish the methodology of a population strategy for improving cardiovascular risk factors, we have planned the High-risk and Population Strategy for Occupational Health Promotion Study (HIPOP-OHP study). This study is a nonrandomized control trial in approximately 6500 participants in six intervention and six control companies. Our population strategy is based on three factors, nutrition, physical activity, and smoking. For each factor, a researchers working team was organized and has been supporting the intervention. A standardized method to obtain comparable data has also been established. In the baseline survey, urinary sodium excretion in male subjects was higher, and urinary potassium excretion was lower in both genders in the intervention group compared to the control group. The prevalence of hypertension for both genders was also higher in the intervention group. Male subjects in the intervention group had higher serum total cholesterol than controls, while high-density lipoprotein cholesterol was lower in both genders in the intervention group compared to the control group. These differences were reflected by our finding that the predicted relative risk of coronary heart disease for male subjects was significantly higher in the intervention group (relative risk, RR: 1.17; 95% confidence interval, 95% CI.: 1.09, 1.25) and significantly lower in the control group (RR: 0.93; 95% CI.: 0.89, 0.98) compared to a model Japanese population. Similar results were observed in the female subjects. Taken together, these findings indicate that it is possible to compare trends of predicted relative risk for coronary heart disease between two groups.

Gender differences in the association between maternal smoking during pregnancy and childhood growth trajectories: multilevel analysis

Objectives:This study examines the gender differences in the association between maternal smoking during pregnancy and later growth in childhood.Design:Ongoing prospective cohort study, which is called ‘the Project Koshu’, initiated in the foetal stage to the age of 9–10 years.Setting:Koshu City which was in Japanese rural areaParticipants:The study population comprised children born between 1 April 1991 and 31 March 1999 in Koshu City, Japan, and their mothers. Maternal smoking during early pregnancy was the exposure studied.Main outcome measures:Childhood body mass index (BMI) and BMI z-score trajectories of the children born to the smoking and non-smoking mothers by gender. Multilevel analysis that includes both individual and age as different-level variables was used for statistical analyses.Results:The participating mothers delivered 1619 babies during the study period. Birth weight and anthropometric data were collected from 1603 (at birth, 99.0%), 1358 (at age 3, 83.9%), 1248 (at age 5, 77.1%), 1270 (at age 7–8, 78.4%) and 1274 (at age 9–10, 78.7%) of these children. The mean birth weight of both the male and female children whose mothers had smoked during pregnancy was significantly low compared with those born to non-smoking mothers (P<0.01). However, the childhood BMI at each subsequent checkup age significantly increased only among the male children born to the smoking mothers. Moreover, this increase was continuously observed after 3 years of age. The results of BMI z-score analysis were also similar to these of BMI analysis.Conclusions:Smoking by pregnant women decreases the infant birth weight irrespective of gender but increases childhood weight gain especially by male children. The results might be valuable to explore the mechanism of fetal programming.

Effectiveness of a Low-Intensity Intra-Worksite Intervention on Smoking Cessation in Japanese Employees: A Three-Year Intervention Trial

Effectiveness of a Low‐intensity Intra‐Worksite Intervention on Smoking Cessation in Japanese Employees: A Three‐Year Intervention Trial, Hideo Tanaka, et al. Department of Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases—To test the effectiveness of a low‐intensity intervention program for smoking cessation targeting the worksite environment in employees who had a low readiness to quit, we conducted an intervention trial at six intervention and six control worksites in Japan. A total of 2,307 smokers at baseline who remained at their worksite throughout the three‐year study period were analyzed (1,017 in intervention and 1,290 in control groups). The multi‐component program at the worksites consisted of (1) presenting information on the harms of tobacco smoking and the benefits of cessation by posters, websites, and newsletters; (2) smoking cessation campaigns for smokers; (3) advice on designation of smoking areas; and (4) periodic sitevisits of the designated smoking areas by an expert researcher. At baseline, the intervention and control groups each had high prevalence of immotive or precontemplation, that reflected low readiness to quit (71.5% and 73.2%, respectively). The smoking cessation rate, as not having smoked for the preceding six months or longer, assessed at 36 months after the baseline survey by a self‐administered questionnaire was significantly higher in the intervention group than the control group (12.1%, vs. 9.4%, p=0.021). The intervention program still had a significant effect on the smoking cessation rate after multiple logistic regression analysis adjusted for sex, age, type of occupation, age of starting smoking, quit attempts in the past, number of cigarettes per day, and readiness to quit (odds ratio: 1.38, 95% confidence interval: 1.05–1.81, p=0.02). The cost per additional quitter due to the intervention was calculated to be ¥70,080. These findings indicate that this program is effective and can be implemented in similar workplaces where the prevalence of smoking is high and smokers’ readiness to cease smoking is low.