Being born extremely preterm was associated with inferior health related quality of life at the age of ten, particularly for the boys. Nearly three out of four preterms had problems related to school performance, compared to one out of five born at term. Academic concerns were related to quality of life in all participants, but more strongly in preterms.
Strengths and limitations
The major strengths of this study were the population-based design and the complete participation. Since there were no subjects with major impairments, there were no exclusions in the analyses, increasing the study's validity for prematurely born children expected to follow a normal social progress during childhood. On average, only 1.3 term born subjects had to be approached to recruit a complete control population, limiting potential sample bias. The same team conducted all parts of the study, limiting inter-observer variability. The major weakness of the study was the relatively low overall number of participants, which made it susceptible to statistical type II errors and thus weakening particularly negative conclusions. However, the reported associations were marked and consistent, and appeared statistically robust. Control subjects were selected with the intention to create a group as similar to the preterm group as possible, with one exception only, the gestational age at birth. Preterm birth has been associated with socioeconomic shortcomings [
27], and one may argue that a control population should reflect this. However, the Norwegian society is characterized by a fairly egalitarian sociodemographic structure, and therefore we opted to match control subjects on gender and the timing of birth only. In this study, we observed a tendency for a lower educational level in mothers of preterms compared to mothers of control subjects, but no such tendency for the fathers. These factors did not influence the conclusions of the study.
Knowledge about HRQoL in school-aged children who were born extremely preterm is relatively scarce. Assessment of a subjective phenomenon like quality of life through information provided by others, in this study the parents, has limitations. However, when self-reported data are difficult or impossible to obtain, this is a valid method to generate information [
9,
13]. Also, parental reports will reflect the challenges of these children and of their families such as they are perceived by the most important person in the life of a child - the parent.
The potential burden of raising a preterm child starts the very minute the parent(s) leave the NICU. Thereafter, a continuously changing panorama of new circumstances and potential difficulties will materialize with the growth of the child, challenging the family structure and its members. A positive finding from the present and similar studies was that parents of the preterm children reported overall family relationships to be good[
10,
28], and that fewer parents in the preterm group had divorced. These findings seemingly contradict the observed CHQ-PF50 scores, which indicate an increased burden of parenting. This result suggests that some forms of adjustment, acceptance, or coping mechanisms are activated within the family by the uncertainty of raising these children. One third of preterm parents reported insufficient societal professional support. Recent reports from the USA and Denmark support this finding [
29,
30]. Lack of professional support may be another factor increasing the observed burden of parenting. Alternatively, there may be inherent challenges involved in the process of parenting many preterm children, making it difficult to offer or receive outside help. It is of considerable interest in this context that two quite different social welfare systems, namely those of Norway and the USA, both seem to fail in providing adequate help for these families.
The school is an arena of utmost importance for both academic and social success in life. As preterm children were reported to have more learning difficulties and/or attention problems, they naturally received more support, both academically and psychologically. In a previous study from our institution, eleven year old children with birth weights less than 2000 g without major disabilities had twice as many school problems and were referred to the School Psychological Services two to three times more often than children born at term [
31]. In the present study, this ratio approached four times that of their matched peers born at term, probably because our preterm cohort was more immature at birth. Similar concerns with respect to academic performance have also been expressed by others examining populations relatively similar to ours [
32‐
34]. The observed association between learning and/or attention problems at school and quality of life was present in all participating subjects, but was more prominent among those born preterm. Why academic shortcomings had a greater negative influence on the quality of life in children born preterm and their parents cannot be answered within the frame of this study since we did not assess the nature and the extent of the learning and attention problems.
Physical activities and sports are important elements of a normal childhood, influencing subsequent physical as well as social development. Neurosensory and cognitive abilities, neuromotor skills, aerobic capacity and personal ambitions influence the extent of individual success. Compared to term born controls, the preterms took less part in physical activities and sports, while they participated to a similar extent in other nonphysical, extracurricular activities. We are not aware that others have reported this pattern. Typical features of children born preterm, e.g. a sense of insecurity, clumsiness, attention problems and reduced physical capacity [
3,
35,
36] may limit their ability and subsequent interest in physical activities. Participation in non-physical social activities might provide an important alternative arena for psychosocial training. Considering the well described tendency towards behavioral problems and reduced social competence in this group of children [
4,
37‐
39], this finding is encouraging. At the age of ten, parents have a strong influence on the choice of activities and lifestyle of their children and one explanation may be that parents of preterms acknowledge their children's physical limitations and therefore encourage them to take part in activities felt to be appropriate and within their physical and mental abilities. A contributing factor to the high rate of participation in non-physical social activities might be that at this age the full impact from potential limitations was not sufficiently obvious to discourage participation.
The excess of concerns and poorer HRQoL scores among the preterm children were mainly explained by the poorer results for the boys. This finding is in line with previous studies on preterm subjects, but contradicts similar studies in unselected populations of similar ages [
10,
40,
41]. Male gender is a well known risk factor for neonatal mortality and morbidity in preterm neonates. In the present study, the boys had a neonatal history characterized by nearly twice as many days of oxygen supplementation compared to the girls. Statistical handling of this situation is difficult, i.e. which is the "true" explanatory factor: gender or prolonged oxygen requirements. However, within the frame of the present study, male gender and not neonatal oxygen treatment appeared as the most important and most robust explanatory variable. It has been suggested that a poorer prognosis in terms of survival and early morbidity for boys also extends to their later development, even for survivors without major disabilities [
42,
43]. Hintz et al. propose that there may be a gap in the societal support offered to boys in their first two years of life [
30]. Why males are more vulnerable than females may partly be explained by a biological fragility of the male fetus, possibly reinforced by an attitude from society that boys are, or must be mademore resilient than girls, thus adding "a social insult to the biologicalinjury" (S. Kraemer p. 1609) [
44]. Based on the present study, one might suggest that this should have implications also for the clinical management of males in a NICU setting, as well as for the upbringing of male children born extremely preterm.
Within the preterm group, subjects who had received neonatal corticosteroid treatment scored poorer in the domain of social functioning. In this context one must bear in mind that corticosteroids are used to treat severely ill neonates with a number of potential risk factors for poor outcome. However, the observation agrees with an accumulating number of reports that neonatal treatment with corticosteroids is associated with an increased risk of impairments [
45]. Apart from this notable exception, there were no associations between the assessed neonatal and perinatal variables and subsequent HRQoL outcomes. This contradicts findings reported by our own group and by others regarding physical outcomes such as lung function and pulmonary CT scans [
6,
46]. One may argue that impact from a diverse postnatal environment will influence multidimensional outcomes such as HRQoL more than unidimensional physical outcomes. Additionally, the neonatal history of extreme preterms varies considerably and most medical problems somehow tend to be interrelated, complicating research on subsequent cause and effect relationships. Also, the limited sample size may have precluded our ability to detect potential associations that might be present. In fact, neonatal treatment with corticosteroids has been reported to have an adverse effect on academic achievement at the age of eight and maternal infection has been reported to predict neurodevelopmental impairments [
2,
47]. Randomized long-term follow-up studies must be performed to explore these issues.