Secondary Data Analysis of National Surveys in Japan Toward Improving Population Health

Association Between Dinner-to-Bed Time and Gastroesophageal Reflux-Related Diseases in Children

INTRODUCTION

Gastroesophageal reflux disease (GERD) is characterized by esophageal mucosal injury due to the reflux of gastroduodenal contents. Typical symptoms include heartburn and acid regurgitation. In addition, gastroesophageal reflux (GER) can influence conditions such as otitis media, rhinitis, and asthma. This study aimed to examine the association between dinner-to-bed time and GER-related diseases, such as otitis media, allergic rhinitis, and asthma.

METHODS

This was a longitudinal cohort study using secondary data. Data were collected from a large-scale birth cohort study conducted in Japan including babies born in 2001 and 2010. Dinner-to-bed time was categorized as "longer dinner-to-bed time" (>120 minutes), "shorter dinner-to-bed time" (≤120 minutes or less), and "irregular dinner-to-bed time." Modified Poisson regression with robust variance was used to estimate risk ratios (RRs).

RESULTS

A total of 60,392 children were included in this study. Children with shorter dinner-to-bed time had a higher risk of asthma (adjusted RR (aRR) = 1.10; 95% confidence interval (CI), 1.03-1.18) than those with longer dinner-to-bed time. However, no significant association was observed between shorter dinner-to-bed time and otitis media or allergic rhinitis. Furthermore, supplementary analyses revealed that the risk of asthma was significantly higher in children born in 2001 (aRR = 1.13; 95% CI, 1.04-1.22).

CONCLUSION

This study showed that dinner-to-bed time within 120 minutes after dinner increases the risk of developing asthma. This underscores the importance of considering lifestyle modifications, as certain pediatric asthma cases may be influenced by behaviors that promote GER.

Evaluating the harmonization potential of oral health-related questionnaires in national longitudinal birth and child cohort surveys

BACKGROUND/OBJECTIVES

Effective use of longitudinal study data is challenging because of divergences in the construct definitions and measurement approaches over time, between studies and across disciplines. One approach to overcome these challenges is data harmonization. Data harmonization is a practice used to improve variable comparability and reduce heterogeneity across studies. This study describes the process used to evaluate the harmonization potential of oral health-related variables across each survey wave.

METHODS

National child cohort surveys with similar themes/objectives conducted in the last two decades were selected. The Maelstrom Research Guidelines were followed for harmonization potential evaluation.

RESULTS

Seven nationally representative child cohort surveys were included and questionnaires examined from 50 survey waves. Questionnaires were classified into three domains and fifteen constructs and summarized by age groups. A DataSchema (a list of core variables representing the suitable version of the oral health outcomes and risk factors) was compiled comprising 42 variables. For each study wave, the potential (or not) to generate each DataSchema variable was evaluated. Of the 2100 harmonization status assessments, 543 (26%) were complete. Approximately 50% of the DataSchema variables can be generated across at least four cohort surveys while only 10% (n = 4) variables can be generated across all surveys. For each survey, the DataSchema variables that can be generated ranged between 26% and 76%.

CONCLUSION

Data harmonization can improve the comparability of variables both within and across surveys. For future cohort surveys, the authors advocate more consistency and standardization in survey questionnaires within and between surveys.

Pediatric otitis media in Japan: A nationwide longitudinal study of the pre- and post-pneumococcal conjugate vaccine eras born in 2001 and 2010

BACKGROUND

Otitis media (OM) is a prevalent respiratory disease in children and poses significant public health challenges due to its impact on child health and economic burdens. However, there have no nationwide epidemiological studies conducted in Japan. This study investigates the epidemiological trends of OM in Japan, taking into account the impact of the 7-valent pneumococcal conjugate vaccine (PCV7) introduction.

METHOD

This study was retrospective cohort study using secondary data on the nationwide longitudinal birth cohort. This survey followed two cohorts born in 2001 (pre-PCV era) and 2010 (post-PCV era) until the age of 9. Every year, parents were surveyed about their children's health status, including occurrences of OM. The annual period prevalence and cumulative incidence of OM were assessed in this study, and the two cohorts were compared using a modified Poisson regression model adjusted environmental factors with the 2001 cohort as reference.

RESULT

The study included 47,015 children from the 2001 cohort and 38,554 from the 2010 cohort. Peak annual period prevalence of OM varied by era. Cumulative incidence was 13.8 % for the 2001 cohort and 18.5 % for the 2010 cohort by 1.5 years of age and 28.9 % and 33.3 %, respectively, by 3.5 years of age. In particular, from the fourth survey onward, covering ages 2.5-3.5 years, a shift was observed from an increased risk to a decreased risk of OM.

CONCLUSION

This nationwide longitudinal study emphasizes variations in OM epidemiology across Japan over time, with changes potentially influenced by the introduction of PCV7. In this study, due to the absence of individual PCV7 vaccination data, the effect of PCV7 was estimated based on the vaccination rate at the population level. The results suggest a notable decrease in the incidence of OM in later years, aligning with the increased uptake of PCV7.

Prevalence and Correlates of Hypertension among Japanese Adults, 1975 to 2010

We investigated the prevalence and factors associated with hypertension, its treatment, and control using individual-level data from 300,249 respondents aged 20 years and older from the Japanese National Health and Nutrition Survey for the period of 1975–2010. We applied multivariate random effects logistic regression to assess associations between the risk factors and the prevalence of hypertension, the proportion of uncontrolled hypertension, and the proportions of respondents seeking treatment and controlling hypertension. The trends in the effect of the birth cohort on uncontrolled hypertension were also examined. Having hypertension was associated with being male, older, obese, drinking alcohol, and working in the primary industry and a higher proportion of middle-aged men than women were found being obese and drinking alcohol. Seeking treatment was associated with being older, obese, drinking alcohol, working in a primary industry and exercising. Controlling hypertension was associated with being younger, underweight and exercising. The proportion of individuals with uncontrolled hypertension declined for cohorts born in later years with a steeper decline for women than men. Raising awareness in the hypertensive population, especially among men, could help further reduce the prevalence of hypertension in Japan.