Pediatrics International (2015) 57, 849–855
doi: 10.1111/ped.12629
Original Article
Association among number, order and type of siblings and adolescent mental health at age 12 Jufen Liu,1,3 Michikazu Sekine,3 Takashi Tatsuse,3 Yuko Fujimura,3 Shimako Hamanishi3 and Xiaoying Zheng2 1 Institute of Reproductive and Child Health, Ministry of Health Key Laboratory of Reproductive Health, Department of Epidemiology and Biostatistics, School of Public Health, Peking University, 2Institute of Population Research, Peking University, Beijing, China and 3Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan Abstract
Background: Although the sibling relationship is a unique one, the effects of the number and type of siblings on mental health among adolescents have not been reported. Methods: Japanese children (total, 9276; boys, 4654; girls, 4622), all 12 years old, and from the Japanese Toyama Birth Cohort Study, were followed up until 2002. Subject self-reported mental health was obtained from the Japanese version of the Dartmouth Primary Care Co-operative Project (COOP) charts. The associations between number and type of siblings and self-reported mental health were examined. Results: There was a significant difference in mental health between different sibling pairs, with brother pairs and brother/sister pairs having a positive effect on adolescent mental health, compared with those in sister pairs. Girls with brothers had better self-reported mental health than those without. The adjusted OR of good mental health was 1.44 (95%CI:1.00–2.08) for those with an older brother and 1.67 (95%CI: 1.17–2.38) for those with a younger brother compared with those without. Boys with a younger sister had a higher OR of good self-reported health than those without (OR, 1.62; 95%CI: 1.08–2.43). Conclusions: Children with siblings had better mental health status than those without, which has practical implications for Asian countries and worldwide considering the declining fertility.
Key words birth cohort, mental health, quality of life, sibling.
The sibling relationship is a unique relationship because of the daily companionship shared in childhood and the lifelong nature of sibling bonds.1 Despite the absence of a single comprehensive sibling theory, several dimensions of sibling relationships consistently emerge in the literature: warmth, conflict, and differential treatment.2 Sibling warmth reflects positive aspects of the relationship such as affection, support, companionship, and closeness whereas sibling conflict consists of negative aspects such as arguing, fighting, aggression, hostility and negativity. Differential parental treatment indicates whether children perceive that their parents behave differently toward them compared with their sibling.3,4 The average number of children per household in Japan has been around 2.4 until recently,5 and a previous study showed that around 93% of Japanese children have a sibling.6 Although sibling relationships provide an important context for development and strongly affect psychosocial functioning,7 they are one of the most neglected relationships in psychological
Correspondence: Michikazu Sekine, MD, PhD, MBA, MSc, DLSHTM, Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan. Email: [email protected] Received 5 October 2014; revised 22 February 2015; accepted 6 March 2015. © 2015 Japan Pediatric Society
research and practice. Previous research has mainly focused on sibship and disease, and has shown that sibship size has a protective effect against allergies8 and being overweight.9,10 Epidemiological studies on the relationship between siblings and mental health have mostly come from Western countries, and few studies exist in Asia. A systematic review showed that sibling conflict was significantly associated with more internalizing and externalizing problems among Caucasian subjects,3 and the most common type of childhood victimization is peer or sibling assault across cultures.11 Children and adolescents victimized by siblings reported worse mental health compared with non-victims.12 A study from Cambodia showed that increased levels of depressive symptoms were significantly associated with sibling caregiving among boys and girls, which indicates that responsibility for sibling care might have a negative impact on the mental health of adolescent caregivers.13 There were no differences according to sex in that study. Another study reported that there was a gender difference in mental health, with the prevalence of depressive disorders being higher in girls than in boys beginning at mid-puberty and persisting through adult life.14 Chen et al. examined gender differences in mental health, but only among Japanese adolescents;15 the effects of the sibling relationship have not yet been studied. A comparison study from China showed that there was no significant difference in selfconcept between children with siblings and only children, although
850 J Liu et al. boys scored higher than girls,16 but the sample size in that study was
doi: 10.1111/ped.12629
Original Article
Association among number, order and type of siblings and adolescent mental health at age 12 Jufen Liu,1,3 Michikazu Sekine,3 Takashi Tatsuse,3 Yuko Fujimura,3 Shimako Hamanishi3 and Xiaoying Zheng2 1 Institute of Reproductive and Child Health, Ministry of Health Key Laboratory of Reproductive Health, Department of Epidemiology and Biostatistics, School of Public Health, Peking University, 2Institute of Population Research, Peking University, Beijing, China and 3Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan Abstract
Background: Although the sibling relationship is a unique one, the effects of the number and type of siblings on mental health among adolescents have not been reported. Methods: Japanese children (total, 9276; boys, 4654; girls, 4622), all 12 years old, and from the Japanese Toyama Birth Cohort Study, were followed up until 2002. Subject self-reported mental health was obtained from the Japanese version of the Dartmouth Primary Care Co-operative Project (COOP) charts. The associations between number and type of siblings and self-reported mental health were examined. Results: There was a significant difference in mental health between different sibling pairs, with brother pairs and brother/sister pairs having a positive effect on adolescent mental health, compared with those in sister pairs. Girls with brothers had better self-reported mental health than those without. The adjusted OR of good mental health was 1.44 (95%CI:1.00–2.08) for those with an older brother and 1.67 (95%CI: 1.17–2.38) for those with a younger brother compared with those without. Boys with a younger sister had a higher OR of good self-reported health than those without (OR, 1.62; 95%CI: 1.08–2.43). Conclusions: Children with siblings had better mental health status than those without, which has practical implications for Asian countries and worldwide considering the declining fertility.
Key words birth cohort, mental health, quality of life, sibling.
The sibling relationship is a unique relationship because of the daily companionship shared in childhood and the lifelong nature of sibling bonds.1 Despite the absence of a single comprehensive sibling theory, several dimensions of sibling relationships consistently emerge in the literature: warmth, conflict, and differential treatment.2 Sibling warmth reflects positive aspects of the relationship such as affection, support, companionship, and closeness whereas sibling conflict consists of negative aspects such as arguing, fighting, aggression, hostility and negativity. Differential parental treatment indicates whether children perceive that their parents behave differently toward them compared with their sibling.3,4 The average number of children per household in Japan has been around 2.4 until recently,5 and a previous study showed that around 93% of Japanese children have a sibling.6 Although sibling relationships provide an important context for development and strongly affect psychosocial functioning,7 they are one of the most neglected relationships in psychological
Correspondence: Michikazu Sekine, MD, PhD, MBA, MSc, DLSHTM, Department of Epidemiology and Health Policy, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan. Email: [email protected] Received 5 October 2014; revised 22 February 2015; accepted 6 March 2015. © 2015 Japan Pediatric Society
research and practice. Previous research has mainly focused on sibship and disease, and has shown that sibship size has a protective effect against allergies8 and being overweight.9,10 Epidemiological studies on the relationship between siblings and mental health have mostly come from Western countries, and few studies exist in Asia. A systematic review showed that sibling conflict was significantly associated with more internalizing and externalizing problems among Caucasian subjects,3 and the most common type of childhood victimization is peer or sibling assault across cultures.11 Children and adolescents victimized by siblings reported worse mental health compared with non-victims.12 A study from Cambodia showed that increased levels of depressive symptoms were significantly associated with sibling caregiving among boys and girls, which indicates that responsibility for sibling care might have a negative impact on the mental health of adolescent caregivers.13 There were no differences according to sex in that study. Another study reported that there was a gender difference in mental health, with the prevalence of depressive disorders being higher in girls than in boys beginning at mid-puberty and persisting through adult life.14 Chen et al. examined gender differences in mental health, but only among Japanese adolescents;15 the effects of the sibling relationship have not yet been studied. A comparison study from China showed that there was no significant difference in selfconcept between children with siblings and only children, although
850 J Liu et al. boys scored higher than girls,16 but the sample size in that study was
