Yoshihiro Miyake

Background: Epidemiological studies have suggested a possible association between tooth loss and dementia, yet evidence regarding mild cognitive impairment (MCI) remains limited. Objective: We examined the association between the number of remaining teeth and functional tooth units (FTUs) and the prevalence of MCI. Methods: A total of 8697 adults aged 20–95 years (3786 men and 4911 women) were included. Dental status was assessed visually, excluding third molars. MCI was defined as a score of less than 26 on the Japanese version of the Montreal Cognitive Assessment. Participants were categorized into five groups based on the FTUs of natural teeth (n-FTUs) and total FTUs: n-FTUs ≥10; n-FTUs 6–9 and total FTUs ≥10; n-FTUs 6–9 and total FTUs p for trend <0.0001). Compared with having n-FTUs ≥10, having n-FTUs <6 and total FTUs ≥10, and having n-FTUs <6 and total FTUs <10 were independently associated with a higher prevalence of MCI. There was no association between having 6–9 n-FTUs, regardless of total FTUs, and the prevalence of MCI. Conclusions: Even when occlusal function is maintained through prosthodontic restorations, a reduced number of natural teeth is independently associated with MCI, underscoring the importance of preserving natural dentition for maintaining cognitive health.

Objective: Consumption of dietary fibre has various beneficial effects on human health. In this prebirth cohort study, we examined the association between maternal dietary fibre intake during pregnancy and the risk of childhood behavioural problems in 5-year-old Japanese children. Method: Participants were 1199 mother–child pairs. Maternal dietary intake was assessed using a diet history questionnaire. Emotional problems, conduct problems, hyperactivity problems, peer problems and low prosocial behaviour in children were assessed using the parent-reported version of the Strengths and Difficulties Questionnaire. Results: Significant inverse exposure–response associations were observed between maternal total dietary fibre consumption during pregnancy and the risk of childhood hyperactivity problems and low prosocial behaviour: the adjusted ORs (95% CIs, P for trend) between extreme quartiles were 0.55 (0.33 to 0.90, 0.02) and 0.64 (0.44 to 0.93, 0.004), respectively. Maternal consumption of soluble dietary fibre during pregnancy was independently inversely associated with childhood hyperactivity problems: the adjusted OR (95% CI, P for trend) between extreme quartiles was 0.57 (0.34 to 0.94, 0.03). Maternal consumption of insoluble dietary fibre during pregnancy was independently inversely associated with both hyperactivity problems and low prosocial behaviour in children: the adjusted ORs (95% CIs, P for trend) between extreme quartiles were 0.48 (0.29 to 0.80, 0.009) and 0.63 (0.43 to 0.91, 0.008), respectively. There were no associations between maternal consumption of total, soluble or insoluble dietary fibre during pregnancy and childhood emotional, conduct or peer problems. Conclusions: Higher maternal intake levels of total dietary fibre and insoluble dietary fibre during pregnancy may be associated with a decreased risk of hyperactivity problems and a decreased risk of low prosocial behaviour in 5-year-old children. Maternal soluble dietary fibre during pregnancy may be inversely associated with childhood hyperactivity problems.

Edible mushrooms have long been recognized for their nutritional value. In the Kyushu Okinawa Maternal and Child Health Study, a prebirth cohort study, we examined the association between maternal mushroom intake during pregnancy and risk of childhood behavioral problems in Japanese 5-year-olds. A total of 1199 mother-child pairs were included as study subjects. In the baseline survey, dietary intake was assessed using a diet history questionnaire. In the follow-up survey, emotional problems, conduct problems, hyperactivity problems, peer problems, and low prosocial behavior were assessed using the parent-reported version of the Strengths and Difficulties Questionnaire. Adjustments were made for a priori-selected non-dietary confounders and potentially related dietary factors. A significant inverse exposure-response association was observed between maternal mushroom consumption during pregnancy and risk of childhood peer problems (adjusted odds ratio [OR] between extreme quartiles, 0.58; 95% confidence interval [CI]: 0.31-1.07, p for trend = 0.02) and low prosocial behavior (adjusted OR between extreme quartiles, 0.64; 95% CI: 0.43-0.95, p for trend = 0.02). Higher maternal intake levels of mushrooms during pregnancy may be associated with a decreased risk of peer problems and a decreased risk of low prosocial behavior in 5-year-old children.

Objectives: In view of the lack of epidemiologic information on the relationship between sibship size and the common cold, this prebirth cohort study investigated the association between the number of older siblings and the high frequency of common colds in Japanese children aged 5 years. Methods: The study included 1197 mother–child pairs in the Kyushu Okinawa Maternal and Child Health Study; data were collected through questionnaires. From April 2007 through March 2008, the baseline survey, conducted during pregnancy, collected information on the number of children (older siblings). The questionnaire in the eighth survey (at approximately 60 months postpartum) asked participants about the frequency of common colds in their children since their fourth birthday. We defined high frequency of common colds as experiencing ≥6 common colds since turning age 4 years. Results: Among the 1197 children aged 59 to 71 months, 140 (11.7%) experienced a high frequency of common colds. Compared with having no older siblings, having 1 older sibling and having ≥2 older siblings were independently associated with a lower likelihood of high frequency of common colds at age 5 years. The adjusted odds ratios (95% CI) for high frequency of common colds were 0.67 (0.45-0.99) for 1 older sibling and 0.42 (0.23-0.73) for ≥2 older siblings ( P for trend = .001), using no older siblings as the reference group. Conclusions: This study identified an independent inverse exposure–response relationship between the number of older siblings and high frequency of common colds at age 5 years. Given that the sibling effect is beneficial for colds, it may be necessary to focus on preventing colds in the first child.

Background Epidemiological evidence on the relationship between breastfeeding duration in early childhood and subsequent depressive symptoms in adolescence is limited. This prebirth cohort study examined whether a longer breastfeeding duration was associated with a reduced risk of depressive symptoms in adolescents at 13 years. Methods The study included 872 mother–child pairs. Adolescent depressive symptoms were assessed using a 20-item Center for Epidemiologic Studies Depression Scale score of ≥16. Results The risk of depressive symptoms was 23.2% among the 872 adolescents aged 13 years. A reverse J-shaped association was found between breastfeeding duration and depressive symptoms at 13 years. Compared with <6 months of breastfeeding, 6 to <18 months, but not ≥18 months, of breastfeeding was significantly associated with a reduced risk of depressive symptoms. The adjusted odds ratios (95% confidence intervals) for depressive symptoms at 13 years for <6 months, 6 to <18 months, and ≥18 months of breastfeeding were 1 (reference), 0.58 (0.34−0.99), and 0.78 (0.46−1.32), respectively. Conclusions The present study found a reverse J-shaped association between breastfeeding duration and depressive symptoms at age 13. Breastfeeding for a duration of at least 6 months may be recommended to prevent adolescent depressive symptoms. Impact Epidemiological evidence on the relationship between breastfeeding duration in early childhood and subsequent depressive symptoms in adolescence is limited. The current prebirth cohort study is the first to report a reverse J-shaped association between breastfeeding duration and depressive symptoms at 13 years. Compared with breastfeeding for <6 months, breastfeeding for 6 to <18 months, but not ≥18 months, was significantly associated with a reduced risk of depressive symptoms at 13 years.