Hospitalization in Adolescence and Young Adulthood Among Twins and Singletons: A Swedish Cohort Study of Subjects Born Between 1973 and 1983

Abstract

Children born with non-optimal birth characteristics -that is, are small for gestational age and/or preterm -have an increased risk for several long-term effects such as neurological sequelae and chronic disease. The purpose of this study was to examine whether twins exhibited a different outcome, compared with singletons, in terms of hospitalization during adolescence and early adulthood, and to what extent differences remain when considering the divergence in birth characteristics between singletons and twins. Persons born between 1973 and 1983 in Sweden and surviving until age 13 were included and followed until the end of 2006. Data on birth characteristics, parental socio-demographic factors, and hospitalizations were collected from national registers. Adjusting for parental socio-demographic factors, twins had a higher risk of being hospitalized than singletons (odds ratio, OR = 1.17, 95% confidence interval, CI = 1.10-1.25) and more often due to 'Congenital anomalies' (OR = 1.18, 95% CI = 1.06-1.28), 'Infections' (OR = 1.14; 95% CI = 1.08-1.20), 'External causes of illness' (OR = 1.10, 95% CI = 1.06-1.15), and 'Diseases of the nervous system' (OR = 1.18, 95% CI = 1.10-1.26). Stratifying for birth characteristics, this difference diminishes, and for some diagnoses non-optimal twins seem to do slightly better than non-optimal singletons. Thus, twins with non-optimal birth characteristics had a lower risk of hospitalization than non-optimal singletons on, for example, 'Congenital anomalies' and 'Diseases of the nervous system' (OR = 0.86, 95% CI = 0.77-0.96; OR = 0.88, 95% CI = 0.81-0.97, respectively) and Total (any) hospitalization (OR = 0.87, 95% CI = 0.83-0.92). Among those with optimal birth characteristics, twins had an increased hospitalization due to 'External causes of illness' (OR = 1.07, 95% CI = 1.02-1.13) compared with optimal singletons. Twins have higher hospitalization rates than singletons. In stratifying for birth characteristics, this difference diminishes, and for some diagnoses, non-optimal twins seem to do less poorly than non-optimal singletons.

Different levels of cardiometabolic indicators in multiple vs. singleton children

“…In contrast, the indirect effect (via birthweight) was significant for all those variables, which means that multiples presented lower estimates for anthropometric and body composition measures reflecting mostly their lower birthweight. Multiples have lower birthweight [1–3], which in turn has been associated with lower anthropometric and body composition measurements later in life, in several recent cohorts [6, 21, 22], including Generation XXI [7]. This is explained by the tracking effect, and in this regard, literature shows that BMI and fatness tracks from early life until adulthood [23, 24].…”

“…An offspring of a multiple pregnancy differs from a singleton regarding characteristics such as fetal growth [1, 2], gestational age [1, 3], mode of delivery [3, 4], anthropometric measures at birth [1, 3, 4] and complications during the neonatal period [1, 4].…”

“…Usually, multiples present a lower birthweight, due to intrauterine growth restriction [1, 2] and lower gestational age [1, 3]. Low birthweight is associated with increased risk of neonatal morbidity and mortality, but also with adverse long-term consequences, namely those related with early cardiometabolic programming [5].…”

“…In addition to a slower rate of growth both in utero [1, 2] and during the first years of life [11, 12], multiple babies experience particular circumstances [13] (e.g. : sharing the utero and nutrition during intra uterine life, sharing the mother’s and father’s attention, having a same-age brother/sister), which might be influential throughout life.…”