Association between sodium and potassium excretion estimated from spot urine and socioeconomic status among primary school children and their mothers in Okinawa, Japan.

Hypertension is the greatest and the most preventable risk factor for cardiovascular disease. Excessive sodium (Na) intake and insufficient potassium (K) intake have been identified as risk factors for hypertension. Socioeconomic status (SES) may be related to diet quality. In Japan, few studies have examined the relationship between urinary Na and K excretion and SES in adults, and there are no studies in children. In 2014, 1944 children (1382 households) in all public elementary schools in Yaese town, Okinawa, Japan were recruited to participate in a study. Casual urine specimens were collected to estimate 24-h urinary Na and K excretion and urinary Na/K ratio. Mother's educational background and household incomes were assessed and used as indicators of SES. A total of 236 pairs of children and their mothers were analyzed in this study. Urinary Na and K excretion were not significantly related to educational levels of mothers and household incomes in children. On the other hand, in mothers, lower household income group had higher 24-h estimated urinary Na excretion and urinary Na/K ratio than other groups. There was no significant difference between urinary excretion and educational levels in mothers. Household income disparities in urinary levels seen in mothers were not seen in children. There may be some factors that moderate the dietary inequalities in children.

Impact of the COVID-19 Pandemic on the Socioeconomic Inequality of Health Behavior Among Japanese Adolescents: A 2-Year Repeated Cross-Sectional Survey.

BACKGROUND: Although disparities in socioeconomic status in health behaviors have been highlighted globally, they are not well understood in Japanese adolescents. The purpose of this study was to clarify the changes in socioeconomic disparities in adolescents' fundamental health behaviors, such as physical activity, screen time (ST), sleep, breakfast intake, and bowel movement before and during COVID-19. METHODS: This was a repeated cross-sectional study which used data from the 2019 and 2021 National Sports-Life Survey of Children and Young in Japan. Data of 766 and 725 participants in 2019 and 2021, respectively, were analyzed. Favorable health behaviors were defined as daily moderate to vigorous physical activity (MVPA) of at least 60 minutes, ST of less than 2 hours, sleep of 8 to 10 hours, daily breakfast intake, and bowel movement frequency of at least once in every 3 days. We calculated the slope index of inequality and relative index of inequality in each health behavior for equivalent household income levels for assessing absolute and relative economic inequalities. RESULTS: Compliance with MVPA and ST recommendation significantly declined from 20.1% and 23.0% in 2019 to 11.7% and 14.9% in 2021, respectively. The slope index of inequality and relative index of inequality increased in MVPA for income levels, but decreased in daily breakfast in 2019 to 2021. Although the widening and narrowing of the disparity were inconclusive for ST, it exacerbated for the higher-income groups. CONCLUSIONS: Our study revealed widening of economic disparities in the achievement of recommended MVPA and narrowing of it in breakfast intake among adolescents before and during COVID-19.

Effect of Nutrition Education on the Vegetable Intake of Residents in Okinawa.

Background: Increasing vegetable intake is recommended for promoting health in communities. This study investigated the effects of nutrition education on vegetable intake and the factors associated with changes in vegetable intake among residents of Okinawa. Methods and Results: Subjects (n=1,345; mean [±SD] age 56.8±14.6 years; 40.5% male) were recruited from among local residents participating in the Yui Kenko Project. Subjects completed the brief-type self-administered diet history questionnaire (BDHQ) and questionnaires on socioeconomic demographics and social capital. Subjects were divided into 2 groups according to residential area, namely south Okinawa (n=679), where local health promotion activities have been undertaken since the early 2000s, and central Okinawa (n=666). Survey results were fed back to each subject, and health lectures were then conducted at local community centers. After 1 year, the BDHQ was repeated to investigate changes in vegetable and nutritional parameters. After the intervention, residents of south Okinawa increased their crude and energy-adjusted vegetable intake (P<0.05), whereas residents of central Okinawa showed decreased vegetable intake (P<0.05). Univariable and multivariable regression models indicated that, in south Okinawa, participation in local health promotion activities and agreement with general trust were positively correlated with changes in energy-adjusted vegetable intake, whereas in central Okinawa no correlations were observed. Conclusions: The status of social capital should be taken into account when implementing initiatives to increase vegetable intake in communities.

Urgent need to strengthen school health in Asia and the Pacific islands.

In Asia and the Pacific island region, strengthening of school health activities and measures is urgently recommended to deal with the impact of the increasing risk of potential school closures due to continuation of the coronavirus disease 2019 (COVID-19) pandemic in 2021. As the incidence of COVID-19 in 2020 was relatively low in these regions, many of the countries were able to avoid prolonged school closures. However, even if vaccination is expanded in the future and the pandemic tends to come to an end, the risk of SARS-CoV-2 variants spreading among children will also increase, and the possibility of having to close schools again will also increase.

Time trends of socioeconomic inequalities in adolescent smoking in Okinawa, Japan, 2008-2016: a repeated cross-sectional study.

BACKGROUND: Smoking among Japanese adolescents has decreased noticeably. However, little is known whether the decreasing trend in adolescent smoking can be seen across all socioeconomic status (SES) groups. This study aimed to examine trends in socioeconomic inequalities in smoking among Japanese adolescents between 2008 and 2016. METHODS: We conducted a repeated cross-sectional study using data from three surveys of high school students in Okinawa, Japan, in 2008, 2012, and 2016. The study participants consisted of 7902 students in grades 10 through 12 (15-18 years). Smoking was assessed as current cigarette use. SES indicators included familial SES (parental education and family structure) and student's own SES (school type). To evaluate absolute and relative inequalities, prevalence differences (PDs) and ratios (PRs) between low and high SES groups were estimated. The slope index of inequality (SII) and relative index of inequality (RII) were also calculated. RESULTS: Smoking prevalence among boys and girls significantly declined from 11.5% and 6.2% in 2008 to 4.7% and 1.9% in 2016, respectively. Similar decreasing trends in smoking were found among most of the SES groups. The PDs and SII for parental education in boys and family structure in girls decreased over time while those for school type persisted among boys and girls. The PRs and RII for school type in boys increased while those for other SES indicators among both sexes remained stable over time. CONCLUSIONS: Smoking among Japanese adolescents has been declining and time trends of socioeconomic inequalities in smoking varied by absolute and relative measures. Further policies and/or interventions to reduce smoking inequalities should focus on the context of schools, especially in vocational high schools.

Validation of the Physical Activity Questions in the World Health Organization Health Behavior in School-Aged Children Survey Using Accelerometer Data in Japanese Children and Adolescents.

BACKGROUND: An international physical activity (PA) questionnaire is beneficial to make cross-country comparisons among children and adolescents. This study assesses the validity of the PA questions in the World Health Organization Health Behavior in School-Aged Children (WHO HBSC) survey in Japanese children and adolescents. METHODS: Participants were fifth- to sixth-grade Japanese primary school students (67 students aged 10.8 [0.5] y) and first- to third-grade junior high school students (108 students aged 13.0 [0.7] y). The Japanese version of the PA questions in the WHO HBSC (WHO HBSC-J) was used. To assess the validity of the PA questions, the authors used a partial correlation adjusted for sex, age, and relative weight between the answers to the survey questions and objectively measured moderate to vigorous PA (MVPA) by an accelerometer. RESULTS: A significant positive correlation was found between accelerometer-measured MVPA and the number of reported days with at least 60 minutes/day of MVPA in primary school students (r = .39, P = .002) and junior high school students (r = .32, P < .001). CONCLUSION: The HBSC-J has moderate validity for evaluating MVPA in Japanese primary school and junior high school students.

The Relative Association of Collective Efficacy in School and Neighborhood Contexts With Adolescent Alcohol Use.

BACKGROUND: It is unclear whether either neighborhood collective efficacy or school collective efficacy is associated with adolescent alcohol use. This study aimed to examine the relative contributions of collective efficacy, both in school and in the neighborhood contexts, to alcohol use among Japanese adolescents. METHODS: A cross-sectional study was conducted in public high schools across Okinawa and Ibaraki Prefectures in Japan in 2016. The study participants consisted of 3,291 students in grades 10 through 12 cross-nested in 51 schools and 107 neighborhoods. Alcohol use was measured as current alcohol drinking, which was defined as self-reported drinking on at least 1 day in the past 30 days. Collective efficacy was measured using scales of social cohesion and informal social control in school and the neighborhood. Contextual-level collective efficacy was measured using aggregated school-level and neighborhood-level individual responses, respectively. We used non-hierarchical multilevel models to fit the cross-nested data. RESULTS: Significant variation in alcohol use was shown between schools but not between neighborhoods. After adjusting for covariates, school collective efficacy at individual- and contextual-levels was protectively associated with alcohol drinking (odds ratio [OR] for the increase of one standard deviation from the mean 0.72; 95% confidence interval [CI], 0.63-0.82 and OR 0.61; 95% CI, 0.49-0.75, respectively), whereas neighborhood collective efficacy at individual- and contextual-levels was not associated with alcohol consumption. CONCLUSION: The school-level associations of collective efficacy with adolescent alcohol use may have the greater impact than the neighborhood-level associations. Adolescent drinking prevention efforts should include enhancing school collective efficacy.

Mediating effect of aerobic fitness on the association between physical activity and academic achievement among adolescents: A cross-sectional study in Okinawa, Japan.

The purpose of this study was to examine the potential role of aerobic fitness (AF) as a mediator of the association between physical activity (PA) and academic achievement (AA) among Japanese junior high school students. A cross-sectional data was collected from 608 7th grade students enrolled at five public junior high schools in two suburban municipalities in Okinawa, Japan. Self-reported PA was assessed using the Patient-Centred Assessment and Counselling for Exercise plus Nutrition questionnaire. The 20-meter shuttle run test was performed to determine AF. AA was evaluated using the overall grade point average. Family structure, parental education level, and achievement motives were the self-reported covariates. The results of the bootstrapped mediation analysis indicated that PA had a direct effect on AF, which in turn influenced the AA among boys. After adjusting for AF, the association between PA and AA disappeared while the association of AF with AA still remained. However, neither PA nor AF was associated with the AA of girls. Therefore, the hypothesis that AF might mediate the relationship between PA and AA was supported for boys. Promoting AF, as a result of engaging to PA could positively influence AA particularly in boys.

Does Physical Fitness Affect Academic Achievement among Japanese Adolescents? A Hybrid Approach for Decomposing Within-Person and Between-Persons Effects.

Positive association between physical fitness and academic achievement in adolescents has been suggested yet the causal effect of physical fitness on academic achievement remains unclear. This study examined if longitudinal changes in physical fitness were associated with changes in academic achievement among junior high school students. Analyses were based on a two-year with three time-point data of 567 students (aged 12⁻13 years old at the baseline-point; 303 boys) who entered in five Japanese junior high schools in 2015. Academic achievement was evaluated using the student's overall grade point average. Comprehensive physical fitness score was summed up from eight fitness tests: 50-m sprint, standing broad jump, repeated side-steps, sit and reach, sit-ups, hand-grip strength, handball throw, and 20-m shuttle run or endurance run. The hybrid regression model was applied to examine the impact of change in physical fitness on change in academic achievement using multiple imputation to account for non-response at follow-up. The changes in fitness score within-person and the differences in average of fitness score of three-time points between-person were associated with change in overall grade point average for boys. No significant association between fitness score and overall grade point average was observed in girls. Opportunities for increased physical fitness may be important to support academic achievement, particularly in junior high school boys.

Relations of participation in organized activities to smoking and drinking among Japanese youth: contextual effects of structural social capital in high school.

OBJECTIVES: This cross-sectional study examined the effect of school-level structural social capital on smoking and drinking among Japanese youth. METHODS: Self-administered anonymous questionnaires were distributed to 3248 students at 29 high schools across Okinawa, Japan in 2008. Structural social capital was measured by students' participation in organized activities: student council, extracurricular activities, volunteer activities, community sports clubs, and youth associations. Contextual-level social capital was measured by aggregated school-level individual responses. RESULTS: At the individual level, extracurricular activity participation was negatively associated with smoking and drinking, whereas participation in youth associations was positively associated with smoking and drinking. School-level extracurricular activity participation was negatively associated with smoking among boys, whereas school-level participation in youth associations was positively associated with smoking among boys and girls and drinking among boys. CONCLUSIONS: This study suggests that structural social capital measured by participation in organized activities, especially extracurricular activities, might be an important way for youths to attain good health. This study also supports the idea that particular type of activities, such as youth associations, can lead to the so-called "dark side of social capital".

Does social trust at school affect students' smoking and drinking behavior in Japan?

This study examined the individual and contextual effects of cognitive social capital at school on cigarette smoking and alcohol drinking in Japanese high school students. Self-administered questionnaires were distributed to 3248 students in grades 10-12 (aged 15-18 years) at 29 public high schools across Okinawa, Japan in 2008. The individual-level cognitive social capital studied was generalized trust. Using multi-level logistic regression models, the effects of individual- and contextual-level cognitive social capital on smoking and drinking were analyzed. Contextual-level cognitive social capital was measured on the basis of aggregated individual responses to the trust question at school level. After adjustment for the covariates, individual-level trust was negatively associated with smoking and drinking among boys and girls. Similarly, after adjustment for the covariates, school-level trust showed an inverse association with smoking for girls. A similar but not statistically significant association was observed for boys. On the other hand, school-level trust was not associated with drinking among boys or girls. After adjustment for individual-level trust and the covariates, these findings were in the same direction, but the school-level trust for girls no longer had a significant contextual effect on smoking. The findings suggest evidence of the individual effect of cognitive social capital on adolescents' smoking and drinking, and that the contextual effect of social capital on smoking was inconclusive. In addition, no association of contextual-level social capital with drinking was observed.

The contextual effect of school satisfaction on health-risk behaviors in Japanese high school students.

BACKGROUND: The importance of school contextual effects on health and well-being among young people is currently recognized. This study examines the contextual effects of school satisfaction as well as the effects of individual-level school satisfaction on health-risk behaviors in Japanese high school students. METHODS: Self-administered questionnaires were distributed to 3248 students in grades 10 through 12 at 29 public high schools throughout Okinawa, Japan. Using multilevel logistic regression models, the effects of individual- and contextual-level school satisfactions on health-risk behaviors were analyzed. The contextual-level school satisfaction was defined as satisfaction at the school level and was measured using aggregated individual scores. Behaviors studied included current smoking, current drinking, and sexual activity. RESULTS: Approximately 15%, 6%, and 5% of the total individual differences in smoking, drinking, and sexual behaviors, respectively, occurred at the school level. Students with lower school satisfaction were more likely to engage in health-risk behaviors compared with those with higher school satisfaction. After adjustment for individual-level school satisfaction and other covariates, the odds of smoking and drinking increased with decreasing contextual-level school satisfaction. However, the association of contextual school satisfaction with sexual activity did not reach statistical significance. CONCLUSIONS: This study showed that individual- and contextual-level school satisfactions affected smoking and drinking behaviors in Japanese high school students. However, no significant association between contextual-level school satisfaction and sexual activity was observed.

Relationship of condom use with other sexual risk behaviors among selected Japanese adolescents.

This study examines relationships between condom use and age at initiation of sex, the number of sexual partners, and alcohol or drug use before sex among a convenience sample of 2852 Japanese adolescents. We found that nonuse of condoms is related to early initiation of sex, having multiple sexual partners and alcohol or drug use before sex.

Association of age at onset of cigarette and alcohol use with subsequent smoking and drinking patterns among Japanese high school students.

This study examined relationships between age of smoking and drinking initiation, and subsequent patterns of smoking and drinking among Japanese high school students. Self-administered anonymous questionnaires were conducted using a sample of 1,466 students in grades 10 through 12 at seven public senior high schools in urban areas of Okinawa, Japan. After controlling for demographic variables, students who began smoking at age 12 or younger were more likely to become heavy smokers and heavy drinkers than those who began smoking at ages 15 or older. Age of smoking initiation was not related to risks for current smoking and current drinking. Students who started drinking at age 12 or younger, and at 13 or 14 years, were significantly associated with current smoking, current drinking, heavy smoking, and heavy drinking, compared to students who began drinking at ages 15 or older. Early onset smoking and drinking represent significant predictors for subsequent use of cigarettes and alcohol. These findings suggest that smoking and drinking prevention programs should begin during elementary school.

[Regional differences in relationships between depressive symptoms and psychosocial factors among high school students: a comparison of Okinawa and Saga prefectures].

OBJECTIVES: This study aims to examine regional differences in relationships between depressive symptoms and psychosocial factors among Japanese high school students in Okinawa and Saga prefectures in Japan. METHODS: The study sample was 3,234 students from 14 public high schools in Okinawa and 2,503 students from 12 public high schools in Saga. The students completed a self-administered questionnaire between September and November 2000. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale (CES-D). The psychosocial factors examined were participation in community events, life stress, self-esteem, perceived social support, and life environment. RESULTS: There was no difference in depressive symptoms by region. Students in Saga had higher levels of stress in the academic, teachers' and friends' domains compared to students in Okinawa. Students in Saga also evaluated their natural environment better than their counterparts in Okinawa. On the other hand, students in Okinawa were more likely to participate in community events than those in Saga. After controlling for sociodemographic variables, depressive symptoms were found to be significantly associated with life stress, self-esteem, and social support among students in both Okinawa and Saga. Only among students in Okinawa, however, were depressive symptoms significantly related to participation in community events. The psychosocial factors accounted for the same amount of variance in depressive symptoms for Okinawa and Saga students. Additionally, life stress in the teachers' domain had stronger associations with depressive symptoms among students in Saga than among those in Okinawa. The depressive symptom levels of Okinawa students seemed to be more strongly associated with self-esteem than those affecting their counterparts in the Saga prefecture. CONCLUSION: These findings show that there is similar pattern of associations between depressive symptoms and psychosocial factors among high school students in Okinawa and Saga, except for participation in community events. Life stress, self-esteem, and social support may be common factors associated with depressive symptoms among high school students regardless of region. Overall, the magnitude of the relationship between depressive symptoms and psychosocial factors was similar across Okinawa and Saga students.

Knowledge and behavior relating to malaria in malaria endemic villages of Khammouane Province, Lao PDR.

In order to provide basic data for evaluation of malaria control measures, a study on the knowledge and behavior of people regarding prevention of malaria was carried out in 8 malaria endemic villages in Khammouane Province of Lao PDR from 1999 to 2000. The total valid questionnaire respondents were 932, with a mean age of 32.3 +/- 14.9. 43.7% of the respondents were illiterate. About 44% of the respondents suffered from malaria in the past. About 55% of the illiterate group slept in mosquito nets, compared to 75.4% for the educated group. About 29% of the illiterate respondents had knowledge of malaria transmission by mosquito bites, compared to 48.8% for the educated groups. Out of 167 non-impregnated mosquito nets examined in two villages, 13 were in bad condition having holes or leaks and 39 female mosquitos including Anopheles spp were collected in these nets by early morning catches. Knowledge of malaria and behavior in relation to the prevention of malaria were significantly related to educational level. Health education as well as general education must be taken into account for communities in malaria endemic areas to become more involved in malaria control strategies.

Entomological surveys of malaria in Khammouane Province, Lao PDR, in 1999 and 2000.

Anopheline mosquitos and their relation to malaria transmission were studied 3 times: in July and August, 1999; in December, 1999; and in August and September, 2000. The studies took place in the malaria endemic villages of Khammouane Province, southeast of Lao PDR. A total of 28 species were collected using human and animal bait. Human bait attracted predominantly Anopheles dirus and An. minimus, which were identified as vectors by the detection of sporozoites by dissection, PCR, and enzyme-linked immunosorbent assays for Plasmodium falciparum and P. vivax. The vectorial capacity of An. dirus was 0.009-0.428, while that of An. minimus was 0.048-0.186. The inoculation rate of An. dirus was 0.052-0.137 (Boualapha; August, 2000). An. nivipes and its sister species, An. philippinensis, were principally zoophilic, although a considerable number of the females were also attracted to human bait in the villages of the paddy field areas. An. philippinensis infected with oocysts of P. vivax was detected in a specimen collected by animal bait. These two species were considered as vectors in Khammouane Province. Four species, An. notanandai, An. sawadwongporni, An. willmori, and An. hodgkini, had not been recored before in Lao PDR. Information is provided on host preference and the nocturnal biting activities of common species and the incidence of malaria in the study areas.