In this study, we have assessed the subjective health-related quality of life in children and adolescents with treated CD, and the corresponding evaluation made by their parents. We found that the children valued their quality of life as very high, but the parents estimated their children's HRQoL as lower than their children.
The results suggest that the children, as a group, have adapted well to the disease. Indeed, in two earlier studies [14
], the authors claim that children with CD who keep a strict gluten-free diet experience the same high HRQoL as healthy children. While being aware that we could lower the sensitivity and specificity by not choosing a disease specific measure [20
], we have used the DISABKIDS chronic generic measure, which is a well-established and validated instrument for assessing HRQoL in children with chronic diseases [18
]. The instrument may be used for different diagnostic groups, and this makes comparisons possible on how distinct diseases affect children's self-estimated quality of life. In a pilot study done by the DISABKIDS group, other chronic diseases, such as asthma, arthritis, dermatitis, diabetes, cerebral palsy, cystic fibrosis, and epilepsy, were tested [18
]. The mean total score for these conditions ranged between 63 and 81 points, with the cerebral palsy children scoring lowest and the asthma children highest. There were no reference values for celiac disease; hence, the present study is to best of our knowledge the first to show values for CD using this instrument. The CD children in our study scored higher than the children affected by other chronic diseases both in total score and in the three domains of the questionnaire.
Measurements of HRQoL based on life situations are difficult to perform, since both subjective and objective circumstances must be taken into consideration. It has been reported that children's compliance to a gluten-free diet was correlated with the parent's knowledge and understanding of the disease. This in turn was highly correlated with the social status of the families [21
]. In the present study, neither the socioeconomic factors of the family, nor the parents' occupation, education, or the living environment have been highlighted. However, in order to elucidate the significance of different factors on the quality of life, we related the HRQoL of the children to age, sex, years since diagnosis, age at diagnosis, and the severity of the disease at onset. The results show that sex had no impact on the HRQoL, neither had age as a single factor.
Children who were diagnosed before the age of five scored better than those who were five years or older at the diagnosis. Furthermore, we noted that children who had had their disease for a long time experienced their current quality of life as higher. These results are consistent with the report from Högberg et al. [22
], where children who were diagnosed before the age of four accepted their illness and the gluten-free diet better than those who were diagnosed later. The young children have probably not been accustomed to the taste of gluten-containing food, which may result in a better compliance to the gluten-free diet. There are studies showing that it may be difficult to adapt to a chronic disease during adolescence, the period of life when the needs to be like the others probably are the highest [3
An additional factor influencing the children's HRQoL was the manifestation of the disease at onset. The classification into three groups was done retrospectively by an experienced paediatric gastroenterologist, thereby increasing the reliability of the assessment. The children who presented with the classical form of the disease valued their HRQoL as highest. The majority of the children in this study who were diagnosed before the age of four presented with the typical CD symptoms, for example, diarrhea, failure to thrive, loss of weight, and enlarged abdomen. Currently, the median age at diagnosis has increased, and children receive their diagnosis more often at an older age and present with more diffuse symptoms [25
]. Further studies should be performed on the latter patient group, using the same instrument, in order to reveal the importance of age at diagnosis and disease severity as predictors of HRQoL later in life.
Some children in this study had extremely low scores in HRQoL (). We cannot explain if this is due to celiac disease or due to other factors that were not assessed in this study. Yet, such low values should alert the health professionals to evaluate the need for psychological and social support.
According to Eiser and Morse [26
], parents with chronically ill children are able to make a better valuation of their child's HRQoL as compared to parents with healthy children. In the present study, the parents valued their children's HRQoL as lower than the children themselves did. This was noted both for the total quality of life and for the three domains mental, social, and physical health. Sawyer et al. [27
] described how health care professionals often listen only to the parent's description of the child's problems, which may lead to a misinterpretation of the child's HRQoL by the staff and a risk for overtreatment of the child. Parents of CD children are often worried about possible complications, development of other autoimmune diseases, fertility, and heredity. They are also concerned about what the children have to endure, and what they have to abstain from, and indeed, the greatest discrepancy between children and parents in this study was seen in the domain social health. The parent's lower valuation of their children's HRQoL may also be due to the parent's sense of responsibility and concern as the basis for the valuation [27
]. Many parents feel guilt, sadness, bitterness, and difficulties of coping in the everyday life when their child is diagnosed with a chronic disease. Indeed, parents in all the diagnostic groups in the pilot studies in DISABKIDS valued the children's HRQoL lower than their children did [18
]. Interestingly, when assessing HRQoL in the parents of children with CD, de Lorenzo et al. [13
] found an impaired self-valuation in comparison to parents of healthy children, especially in the social dimension. This suggests an impact of the diet regimen and possibly other factors on the parents and on close relatives, a suggestion that was also proposed by Sverker et al. [7
The parent's valuation was also affected by the age of the child at the time of diagnosis. The younger the child was at onset, the better was the parent's valuation of its present HRQoL. This may be due to the fact that the youngest children also had the most severe symptoms of the disease and, hence, were the ones that most obviously benefitted from the gluten-free diet. Furthermore, parents of children who had the diagnosis for a long time tended to value their child's quality of life higher, possibly reflecting that the families were getting used to the diet regimens and all the difficulties that could come out of it.
One important limitation of the present study was the lack of a control group of healthy individuals. However, the instrument used in the study was developed to address children with chronic diseases making the use of a healthy control group difficult. Furthermore, while our study group had higher HRQoL than groups with other chronic diseases, other studies reported that children with CD generally had high values in HRQoL measurements and that the values were similar to the control groups [13
]. On the contrary, when assessing psychological symptoms in treated CD children and controls, Mazzone et al. [6
] found signs of more depression and anxiety in the CD group, indicating an influence of the strict diet regimen on the child's psychological well-being, something that health care professionals should be aware of.
The reason for using HRQoL instruments in health care is to get a combined picture of the mental, social, and physical health of the child. This could help the health care professionals in getting a clearer view of how the children and their relatives experience chronic diseases. In the present study, it was important that both the celiac child and the parents made an estimation of the child's current HRQoL, in order to improve our knowledge of the living conditions for celiac families.
In conclusion, children who were diagnosed before the age of five and who presented with the classical form of CD scored their health-related quality of life higher. The children who have had the disease for a longer time also scored higher. The celiac children in this study scored higher than other diagnostic groups assessed with the same instrument. Notably, the parents scored significantly lower than the children when they were asked to evaluate their child's HRQoL. The disagreement between the self- and the proxy valuations highlights the importance of letting the children themselves be heard about their perceived quality of life.