Norito Kawakami

The Job Content Questionnaire (JCQ): an instrument for internationally comparative assessments of psychosocial job characteristics.

Part I discusses the Job Content Questionnaire (JCQ), designed to measure scales assessing psychological demands, decision latitude, social support, physical demands, and job insecurity. Part II describes the reliability of the JCQ scales in a cross-national context using 10,288 men and 6,313 women from 6 studies conducted in 4 countries. Substantial similarity in means, standard deviations, and correlations among the scales, and in correlations between scales and demographic variables, is found for both men and women in all studies. Reliability is good for most scales. Results suggest that psychological job characteristics are more similar across national boundaries than across occupations.

Development of a screening questionnaire for tobacco/nicotine dependence according to ICD-10, DSM-III-R, and DSM-IV.

A 10-item questionnaire (the Tobacco Dependence Screener; TDS) for screening of tobacco/nicotine dependence according to ICD-10, DSM-III-R, and DSM-IV was newly developed. The reliability and validity were assessed in three samples of smokers in Japan. A total of 58 male smokers completed the TDS and the Fagerstrom Tolerance Questionnaire (FTQ), and they were interviewed using the World Health Organizations Composite International Diagnostic Interview (Sample 1). A total of 118 male and 36 female smoking outpatients completed the TDS and the FTQ and provided a breath sample for carbon monoxide measurement (Sample 2). A total of 194 male smokers joined a health education program using a health risk appraisal (HRA) and reported their smoking status and completed the TDS 6 months after receiving the HRA results (Sample 3). The Cronbachs alpha coefficients for the TDS ranged from .74 to .81 among the samples, whereas those for the FTQ ranged from .41 to .64. Receiver operator characteristic analyses indicated that the TDS had a better screening performance for ICD-10, DSM-III-R, and DSM-IV diagnoses than did the FFQ. The TDS score significantly and positively correlated with the severity of the diagnoses, the carbon monoxide levels, number of cigarettes smoked per day, and years of smoking. The TDS score was significantly lower in those who quit smoking than in those who did not quit smoking after the HRA. It is suggested that the TDS is a reliable and useful screening questionnaire for tobacco/nicotine dependence according to ICD-10, DSM-III-R, and DSM-IV.

Japan-U.S. comparison of responses to depression scale items among adult workers

The operating characteristics of the Center for Epidemiologic Studies Depression Scale were compared between Japanese and U.S. adult workers. Data were analyzed from age- and education-matched male white collar workers (n = 368 for each) selected from 2016 workers in Japan and 3059 in the United States. The U.S. data were obtained from the 1974-75 Augmentation Survey of the National Health and Examination Survey I. The Japanese responses to positively worded items markedly differed from those of U.S. workers, whereas responses to negatively worded items were generally comparable in the two groups. Thus, spuriously higher positive subscale and whole scale scores were found among the Japanese workers compared with U.S. workers (mean scores: 6.03 vs. 1.83 for the positive subscale and 9.94 vs. 5.35 for the whole scale, respectively; both differences were statistically significant). Negative subscale scores did not differ significantly in the two samples (3.91 vs. 3.52). The present study confirmed the hypothesis of Iwata et al. that Japanese respondents have a tendency to suppress the expression of positive affect.

Association of diet and other lifestyle with onset of menopause in Japanese women

OBJECTIVES To evaluate the cross-sectional relationships of dietary and other lifestyle variables to menopause. METHODS A total of 4186 female residents aged 45-55 in Takayama City, Japan, responded to a self-administered questionnaire (the response rate was 89.3%). Diet in the past year was assessed by semiquantitative food frequency questionnaire. Using the logistic regression model, associations between study variables and menopausal status were estimated in terms of odds ratio (OR). RESULTS Nulliparity and lower relative weight were significantly associated with menopause after controlling for age (P < 0.05). The association of smoking with menopause was marginally significant after controlling for age (P = 0.06). Higher intakes of fat, cholesterol, and coffee were inversely and significantly associated with later menopause after controlling for age, total energy, parity, menarche age, and relative weight (ORs for the highest tertiles of fat, cholesterol and coffee intakes were 0.78, 0.79, and 0.70, respectively, P < 0.05). The highest tertiles of calcium and soy product intakes were significantly associated with menopause after controlling for the covariates (ORs = 1.25 and 1.42, respectively, P < 0.05), but postmenopausal women who had menopause at later age showed higher calcium intake than those who had menopause at early age. CONCLUSION Dietary factors appear to be associated with onset of menopause.

Trends in the incidence rate and risk factors for breast cancer in Japan

The incidence rate of breast cancer in Japanrose more than two-fold from 1959–60 to 1983–87.To assess to what extent this increase canbe explained by changes in the prevalence offour major risk factors of breast cancer (i.e.age at menarche, age at first birth, ageat menopause, and parity), we estimated the probabilityof developing breast cancer based on the jointdistribution and relative risks of these four riskfactors. The age-specific incidence rate during 1959–60 reportedby the Miyagi Prefectural Cancer Registry was usedto estimate the baseline hazard rate for womenwithout the four risk factors in the sameage group. Assuming that the baseline hazard rateis constant during all periods, we calculated theexpected incidence rates during the periods of 1959–60,1962–64, 1968–71, 1973–77, 1978–81, and 1983–87 for eachage group. Large discrepancies were noted between theobserved and expected incidence rates during 1983–87 inall age groups. The change in the jointdistribution of the four risk factors accounted forless than 40% of the increase observed from1959–60 to 1983–87, suggesting the effects of otherpowerful risk factors.

A case-control study of myelodysplastic syndromes among Japanese men and women

To determine the risk factors of the myelodysplastic syndromes (MDS) we conducted a case-control study in Japan. One hundred and sixteen MDS patients were diagnosed from 1 September to 31 October 1992 and from 1 August to 31 October 1993 in the 32 hospitals enrolled in the idiopathic Disorders of Hematopoietic Organs Research Committee. Age, sex, and hospital-matched controls were selected for each case. Information on cigarette smoking and drinking habits, hair dye use, history of keeping pet animals, and occupational exposures to organic solvents, lead and radiation was obtained from self-administered questionnaires. Conditional logistic regression was applied to this individually matched case-control study and odds ratios (ORs) were computed to estimate association between each exposure variable and risk of MDS. Alcohol drinking was associated with increased risk of MDS (OR = 2.15; 95% confidence interval = 1.12-4.16) and there was a significant trend in risk with increasing amounts of ethanol consumed per week (P < 0.05). We also found elevated ORs for cigarette smokers (OR = 1.80), users of hair dye products (OR = 1.77), and workers exposed to organic solvents (OR = 1.50), although these ratios were not statistically significant. Exposure to pet animals was not associated with risk of MDS. The association observed between alcohol drinking and MDS was still eminent even after adjusted with other variables of cigarette smoking, hair dye use and occupational exposure to organic solvents, and the dose-response relationship was also confirmed.

Effects of job strain on helper-inducer (CD4+CD29+) and suppressor-inducer (CD4+CD45RA+) T cells in Japanese blue-collar workers

BACKGROUND The effects of job strain on helper-inducer (CD4+CD29+) T cells and suppressor-inducer (CD4+CD45RA+) T cells are not clear. METHODS The subjects were 65 male blue-collar workers in a chemical plant in Japan. Perceived job stressors were assessed using the Japanese version of Job Content Questionnaire, i.e., job demands, job control, supervisor support and coworker support. Blood samples were taken from these subjects, and number and percentage of total lymphocytes were calculated for total T cells, helper (CD4+) T cells, suppressor/cytotoxic (CD8+) T cells, helper-inducer (CD4+CD29+) T cells and suppressor-inducer (CD4+CD45RA+) T cells using the double-staining fluorescence. RESULTS Job control significantly and positively correlated with number and percentage of helper-inducer (CD4+CD29+) T cells, after controlling for age, number of cigarettes per day and blood lead concentration (Spearmans partial correlation, p < 0.05), while job demands, supervisor support or coworker support did not (p > 0.05). The job strain index, i.e., the ratio of job demands to job control, significantly and negatively correlated with the percentage of helper-inducer (CD4+CD29+) T cells (p < 0.05). None of the job stress scales significantly correlated with number or percentage of suppressor-inducer (CD4+CD45RA+) T cells (p > 0.05). CONCLUSIONS It is suggested that higher job strain or lower job control is associated with a decrease in helper-inducer (CD4+CD29+) T cells in Japanese blue-collar workers.

Eysenck's personality and tobacco/nicotine dependence in male ever-smokers in japan

To examine the relationship between Eysencks personality traits and tobacco/nicotine dependence in a male population, a random sample of 200 male ever-smokers aged 35 or older from a community in Japan were interviewed using the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI), which yielded ICD-10, DSM-III-R and DSM-IV diagnoses of tobacco/nicotine dependence. They were also asked to complete the Fagerstrom Tobacco Questionnaire (FTQ) and the short-form Eysenck Personality Questionnaire-Revised. A total of 136 subjects completed both the interview and the questionnaire. Neuroticism scores were significantly higher in those who had lifetime diagnosis of tobacco/nicotine dependence according to ICD-10, DSM-IV, or FTQ criteria than nondependent ever-smokers (p < 0.05). Lie scores were significantly lower in DSM-III-R or DSM-IV tobacco/nicotine dependence than in nondependent ever-smokers (p < 0.05). Multiple logistic regression indicated that neuroticism was significantly associated with a higher risk of ICD-10 tobacco/nicotine dependence (p < 0.05), after controlling for age, education, employment status and smoking behaviors; lie score was significantly associated with a lower risk of DSM-III-R tobacco/nicotine dependence (p < 0.05). It is suggested that neuroticism is associated with a higher risk of tobacco/nicotine dependence in male Japanese ever-smokers. A nonconforming and rebellious attitude or reporting bias represented by higher lie score may be associated with lower rates of tobacco/nicotine dependence.

Rationality/antiemotionality personality and selected chronic diseases in a community population in Japan.

OBJECTIVE To clarify the relationships of the rationality/antiemotionality (R/A) personality with past histories of seven chronic diseases and current smoking habits in a community population in Japan. METHODS A questionnaire survey was conducted of all residents aged 35 years old or over (n = 37,287) in Takayama city, Gifu prefecture, Japan; the response rate was 90.3%. Data from 13,091 males and 14,061 females who completed all relevant questions were analyzed. The subjects were asked to complete an 11-item R/A personality scale developed by Grossarth-Maticek et al. (1985). Past histories of seven major chronic diseases and current smoking habit were also asked in the questionnaire. RESULTS Among males, the R/A scale score was significantly lower in those who had stroke, diabetes or allergy than in those who did not. Among females, the R/A scale score was significantly lower in those who had stroke, allergy or stomach cancer than in those who did not. Among females, current smokers had significantly lower R/A scores than non-smokers. After controlling for age, smoking and drinking, the R/A score was significantly and negatively associated with stroke among males and females; it was significantly and negatively associated with diabetes and allergy among males. CONCLUSION Our findings are contrary to those observed in Yugoslavia and West Germany, and suggest a cultural difference in the relationship between the R/A personality and disease occurrence.

Weight Change in Relation to Natural Menopause and Other Reproductive and Behavioral Factors in Japanese Women

PURPOSE To evaluate the effect of menopause on weight change in Japanese women. METHODS Community-based sample of 828 Japanese women who were premenopausal and aged 40 to 54 years completed a self-administered questionnaire asking information on demographic factors, body size, reproductive history and dietary and behavioral factors in 1992. They responded to a follow-up questionnaire asking weight and menopausal status in 1998. RESULTS Women gained weight modestly, on average, 0.17 kg during the 6-year study period. Weight gain was significantly higher in women who remained premenopausal at follow-up than those who had natural menopause during the study period. Weight gain was significantly associated with early menarche in women who had natural menopause and with high parity in women remained premenopausal. CONCLUSION Reproductive factors rather than sociodemographic and behavioral factors appeared to be associated with weight change during the perimenopausal period. Onset of menopause may diminish weight gain. In contrast, early menarche and high parity showed relationships with weight gain.