Public Health Center-based Study Cohort Research Articles

The association of active and secondhand smoking with oral health in adults: Japan public health center-based study.

BackgroundSmoking is one of the major risk factors for oral diseases, and many studies have found that active smoking is closely associated with the prevalence or severity of periodontal disease and fewer remaining teeth. In contrast to the established association between active smoking and oral health, there have been very few studies investigating the effects of secondhand smoking on oral health, and whether secondhand smoking deteriorates oral health has not been fully clarified. The purpose of the present study was to examine whether active and secondhand smoking were associated with the prevalence of severe periodontal disease and number of teeth among Japanese adults.MethodsSubjects were 1,164 dentate adults aged 55–75 years as of May 2005 who participated in both the Japan Public Health Center-Based Study Cohort I in 1990 and a dental survey in 2005. The dental survey was implemented in the Yokote health center jurisdiction, Akita Prefecture. Participating subjects completed a self-administered questionnaire and a clinical oral examination. The association of smoking status with prevalence of periodontal disease was analyzed using a logistic regression, and with number of teeth or functional tooth units of natural teeth (n-FTUs) using a generalized linear model.ResultsAfter adjusting for age, education level, history of diabetes, BMI, alcohol consumption, perceived mental stress, presence of a family dentist, and oral hygiene, the odds ratio (OR) of risk for periodontal disease in male subjects was significantly increased in non-smokers with secondhand smoking only at home (OR = 3.14, 95 % CI: 1.08−9.12, p = 0.036), non-smokers with secondhand smoking both at home and other places (OR = 3.61, 95 % CI: 1.33−9.81, p = 0.012) and current smokers (OR = 3.31, 95 % CI: 1.54−7.08, p = 0.002), compared to non-smokers without secondhand smoking. Further in men, current smokers had significantly fewer numbers of teeth (19.7 ± 6.82) and n-FTUs (4.92 ± 4.12) than non-smokers without secondhand smoking (22.2 ± 6.92, p = 0.014 and 6.56 ± 4.18, p = 0.007). Such significant relationships of smoking status with periodontal disease and dentition were not observed in women.ConclusionsThe present study indicates that active smoking as well as secondhand smoking may have harmful effects on periodontal health in men. Therefore, it is imperative for health and oral health professionals to enlighten people about the negative influence of smoking, not only on their own health but also on others’ health.

Response to Letter Regarding Article, “The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population: The Japan Public Health Center-Based Study Cohort”

Response: We thank Dr Chen for his interest in our article and his valuable suggestions on this topic. As you know, in our study, we found that higher green tea drinking (≥2 cups/d) or coffee consumption (≥1 cup/d) was inversely associated with the risk of cardiovascular disease and stroke, especially of intracerebral hemorrhage.1 In a further analysis, we found significant decreases in the incidence of stroke among participants who drank green tea (multivariable-adjusted hazard ratio [HR], 0.88; 95% confidence intervals [CIs], 0.81–0.95) or coffee (HR, 0.88; 95% CIs, 0.82–0.94) as a whole (≥1 cup/wk) compared with nondrinkers. In addition, the participants who drank green tea ≥4 cups/d (HR, 0.86; 95% …

Letter by Chen Regarding Article, “The Impact of Green Tea and Coffee Consumption on the Reduced Risk of Stroke Incidence in Japanese Population: The Japan Public Health Center-Based Study Cohort”

To the Editor: In a recent study published in Stroke , Kokubo et al1 reported that consumption of green tea and coffee could significantly reduce the risk of stroke; compared with no tea drinking, participants drinking ≥4 cups/d had a 20% reduction in incidence of all strokes, and a similar reduction was found for those drinking coffee ≥2 cups/d compared with no coffee drinking. It would be interesting to see whether or not there were any significant differences in incidence of stroke between participants with drinking tea or coffee as a whole and those that are nondrinkers. The large data from the Japan Public Health Center (JPHC)–Based …

Dietary fiber intake and risk of cardiovascular disease in the Japanese population: the Japan Public Health Center-based study cohort

There has been no study with regard to the association between dietary fibers and the incidence of stroke and coronary heart disease (CHD) in Asia. We investigated the association between dietary fiber and the risk of cardiovascular disease (CVD), which we defined as stroke or CHD, in a Japanese population. We studied 86 387 Japanese subjects (age 45-65 years, without CVD or cancer in 1995 as Cohort I and in 1998 as Cohort II) and used a self-administered questionnaire to follow-up the participants until the end of 2004. Dietary fiber intake was estimated from food-frequency questionnaires comprising 138 food items. After 899 141 person-years of follow-up, we documented the incidence of 2553 strokes and 684 cases of CHD. Multivariable-adjusted hazard ratios (95% confidence intervals (CIs)) of CVD for the third to fifth quintiles of total fiber were 0.79 (0.63-0.99), 0.70 (0.54-0.89) and 0.65 (0.48-0.87) in women, respectively, compared with the lowest quintile. Total fiber intake was inversely associated with the incidence of stroke, either cerebral infarction or intracerebral hemorrhage in women. The results for insoluble fiber in women were similar to those for total fiber, whereas those for soluble fiber were weak. An inverse association of total fiber with CVD was observed primarily in non-smokers (P for trend=0.045 and 0.001) and not in smokers (probability values for interaction between total fiber and smoking were 0.06 and 0.01 in men and women, respectively). Higher total dietary fiber was associated with reduced risk of CVD in Japanese non-smokers.