Structural Equation Modeling of the Relationship of Bone Mineral Density and Its Risk Factors in Japanese Women

Several factors have been reported as risk factors for the development of osteoporosis. In this study, we aimed to examine the relationship among lifestyle factors, biologic factors, and bone mineral density (BMD) using structural equation modeling (SEM). The subjects in the present study consisted of 866 postmenopausal Japanese women aged between 40 and 80 years old. In the analysis by the SEM, we employed a multiple basic model. As the structural variables, lifestyle factors and biologic factors were selected. The goodness of fit index (GFI) of the final model was 0.991 and the Akaike’s information criteria (AIC) showed the lowest value in the peripheral models. The degree of association between biologic factors and BMD was −0.576 (direct association), 0.012 (indirect association), and −0.564 (total association). With regard to the correlation between lifestyle factors and BMD, the degrees of association were 0.085, −0.084, and 0.001, respectively. This study defined a pilot model for factors influencing BMD. Although is remains necessary to conduct further analyses with more valid measurements and constructs, this model indicated that the correlation between BMD and lifestyle factors was lower than that between BMD and biologic factors.

Assessment of Smoking related Risks for Respiratory Symptoms among Elderly People

Disease risk among elderly smokers is considered to be doubled due to their smoking habits and age as compared with elderly non-smokers. The investigators conducted risk assessments of smoking for respiratory symptoms among elderly people.A questionnaire survey on smoking habits and respiratory symptoms was conducted among 3, 000 persons of 56 years of age and over who were randomly selected from suburban residents in a prefecture in Japan in October, 1997. A total 1, 954 or 65.1% of individuals responded, consisting of 42.8% for men and 57.2% for women, with an average age of 73.6 years.In addition to descriptive analysis, multiple logistic regression analysis was conducted. The results are summarized as follows:Smokers accounted for 28.1% of men and 3.6% of women. Among all age-groups, the highest rate of smokers was observed in men of 56-69 years old (34.7%) which was lower than the national average rate for the 60-69 year-old group (56.1% of men and 14.5% of women in ‘97). The odds ratios and 95 percent confidence interval (95%CI) for “having phlegm every day” and “having phlegm for more than 4 days a week” among smokers were 2.06 (95%CI=1.41-3.01) and 2.77(95%CI=1.80-4.27). Significantly higher odds ratios among smokers were also observed for “wheezing” and “shortness of breath when hurrying”.Odds ratios for some respiratory symptoms including “having phlegm for more than 4 days per week” among inhalers were significantly high compared with non-smokers, whereas those among non-inhalers were not significantly different from 1.0.Odds ratios for symptoms of phlegm and wheezing were significantly higher (Odds ratio ≥2.0) among heavy smokers (Brinkman Index [B. I.] >900) compared to non-smokers, while odds ratios of the same symptoms were not different from 1.0 among light smokers (B.I. ≤500).