Development and evaluation of the physical activity questionnaire for elderly Japanese: the Nakanojo study

The Physical Activity Questionnaire for Elderly Japanese (PAQ-EJ) is a self-administered physical activity questionnaire for elderly Japanese; the authors report here on its repeatability and direct and indirect validity. Reliability was assessed by repeat administration after 1 month. Direct validation was based on accelerometer data collected every 4 s for 1 month in 147 individuals age 65-85 years. Indirect validation against a 10-item Barthel index (activities of daily living [ADL]) was completed in 3,084 individuals age 65-99 years. The test-retest coefficient was high (r = .64-.71). Total and subtotal scores for lower (transportation, housework, and labor) and higher intensity activities (exercise/sports) were significantly correlated with step counts and durations of physical activity <3 and >or=3 METs (r = .41, .28, .53), respectively. Controlling for age and ADL, scores for transportation, exercise/sports, and labor were greater in men, but women performed more housework. Sex- and ADL- or age-adjusted PAQ-EJ scores were significantly lower in older and dependent people. PAQ-EJ repeatability and validity seem comparable to those of instruments used in Western epidemiological studies.     

Modification of GEE1 and linear mixed-effects models for heteroscedastic longitudinal Gaussian data

A characterization of GLMs is given. Modification of the Gaussian GEE1, modified GEE1, was applied to heteroscedastic longitudinal data, to which linear mixed-effects models are usually applied. The modified GEE1 models scale multivariate data to homoscedastic data maintaining the correlation structure and apply usual GEE1 to homoscedastic data, which needs no-diagnostics for diagonal variances. Relationships among multivariate linear regression methods, ordinary/generalized LS, naïve/modified GEE1, and linear mixed-effects models were discussed. An application showed modified GEE1 gave most efficient parameter estimation. Correct specification of the main diagonals of heteroscedastic data variance appears to be more important for efficient mean parameter estimation.     

Smokers’ Sexual Behavior and Their Satisfaction with Family Life

Smokers tend to be more impatient and prefer immediate benefits compared with non-smokers. If people follow their primitive instincts they will engage in sexual behavior. Impatient people are more likely to have sex. However, for married people, having sex with a spouse is considered to be an investment in family life. Based on individual level data of Japan General Social Surveys, this paper investigated how sexual behavior differs between smokers and non-smokers. In addition to it, determinants of life satisfaction are also investigated. The important findings through the interval regression model and the ordered probit model are: (1) frequency of sex is positively associated with family satisfaction; (2) unmarried smokers are more likely to have sex than unmarried non-smokers; (3) married smokers are less likely to have sex than married non-smokers. It follows from estimation results that smoking behavior alerts us to his unobserved characteristics before marriage, thus reducing information asymmetry.     

Yearlong physical activity and health-related quality of life in older Japanese adults: the Nakanojo Study

We hypothesized that the health-related quality of life (HRQOL) would be poorer in physically inactive older adults. This was tested in a sample of 73 male and 108 female free-living healthy Japanese participants, age 65-85 years. We measured accelerometer step counts and their metabolic equivalents (METs) throughout each 24-hr period for 1 year. At the end of the year, HRQOL was assessed. Physical activity was grouped into quartiles. HRQOL was poorer in the lowest quartiles of participants with respect to both step count and duration of activity >3 METs; however, our sample showed no better HRQOL in those participants exceeding minimum standards of daily physical activity, corresponding to counts of around 5,500 and 4,500 steps/day and durations of around 13 and 14 min/day in men and women, respectively. Causation cannot be demonstrated from this cross-sectional study, but nevertheless we suggest that elderly individuals should be encouraged to meet such standards of habitual physical activity.     

Socio-economic determinants of suicide in Japan

Japan has the highest suicide rates among the OECD countries and this public health problem seems to be accelerating in over the recent decades. Investigating and understanding the suicidal behaviour is of crucial importance to society and health policy makers. Such an investigation could provide with useful information for those responsible in formulating the national policies on suicide prevention. This study estimates dynamic econometric models for total, male and female suicides in Japan for the period of 1957–2009. Using the ARDL approach to cointegration, we find that the associations of suicide with sociological factors (divorce and fertility rates) were stronger than those with economic factors (per capita GDP and unemployment) for females.     

Impact of formal and informal deterrents on driving behavior

This paper explores, using panel data of traffic accidents in Japan, how formal and informal deterrence affect driving manners. I found through fixed effects and fixed effects 2SLS estimations that formal deterrents, such as police, cause drivers to drive attentively but that this effect is not inversely associated with dangerous driving. Informal deterrents, on the other hand, impede dangerous driving but do not induce drivers to drive more attentively.     

Sex, age, season, and habitual physical activity of older Japanese: the Nakanojo study

The interactions of sex, age, season, and habitual physical activity were examined in 41 male and 54 female Japanese age 65-83 yr, using a pedometer/accelerometer that determined step counts and amounts of physical activity (<3 and >3 metabolic equivalents [METs]) throughout each 24-hr period for an entire year. All 3 measures were greater in men than in women. In women, age was negatively correlated with step count and activity <3 METs, but in men, it was correlated with step count and activity >3 METs. Irrespective of sex or age, all 3 activity variables were low in the winter, peaking in spring or autumn. In the summer, step counts matched the annual average, but durations of activity <3 and >3 METs were, respectively, longer and shorter than in other seasons. These findings have practical implications for those promoting physical activity for older adults.     

A modified likelihood ratio test for the mean direction in the von mises distribution

The likelihood ratio test (LRT) for the mean direction in the von Mises distribution is modified for possessing a common asymptotic distribution both for large sample size and for large concentration parameter. The test statistic of the modified LRT is compared with the F distribution but not with the chi-square distribution usually employed, Good performances of the modified LRT are shown by analytical studies and Monte Carlo simulation studies, A notable advantage of the test is that it takes part in the unified likelihood inference procedures including both the marginal MLE and the marginal LRT for the concentration parameter.     

Testing for the Null Hypothesis of Cointegration with a Structural Break

In this paper we propose residual-based tests for the null hypothesis of cointegration with a structural break against the alternative of no cointegration. The Lagrange Multiplier (LM) test is proposed and its limiting distribution is obtained for the case in which the timing of a structural break is known. Then the test statistic is extended to deal with a structural break of unknown timing. The test statistic, a plug-in version of the test statistic for known timing, replaces the true break point by the estimated one. We show the limiting properties of the test statistic under the null as well as the alternative. Critical values are calculated for the tests by simulation methods. Finite-sample simulations show that the empirical size of the test is close to the nominal one unless the regression error is very persistent and that the test rejects the null when no cointegrating relationship with a structural break is present. We provide empirical examples based on the present-value model, the term structure model, and the money-output relationship model.     

Formal and informal deterrents of crime in Japan: Roles of police and social capital revisited

Using Japanese prefecture-level panel data, this paper examines how the crime rate is affected by formal and informal deterrents as reflected by police and social capital, respectively. Both, however, suffer from the endogeneity problem and therefore the estimation results are biased when regression analysis is conducted. Hence, the fixed effects 2SLS method is employed to control for the endogeneity bias as well as for unobservable fixed effects. As well, the relationship between inequality and crime is examined. The main findings are: (1) police and social capital reduce the crime rate and their effects increase when the endogeneity bias is controlled for through fixed effects 2SLS estimation. (2) The effects of social capital, which is smaller than that of police, is however is reinforced by police through the complementary relationship existing between them.