Psychosocial influences on upper respiratory infectious illness in children

Abstract

Fifty-five boys and 61 girls, aged 5–16 years, took part in a 15-week longitudinal study of stress and upper respiratory infectious illness. Life events, social support, and psychological coping were measured, and hassles and mood were assessed repeatedly throughout the study period. Upper respiratory symptoms were recorded daily, and episodes of upper respiratory infection were verified by clinical examination. Forty-eight verified episodes of infection were recorded from 41 participants (35.3% of the total sample). Life events and social support interacted in predicting the occurrence of infection, whereas hassles interacted with avoidant psychological coping, independently of age, gender, family composition, social class, negative affect, parental perceived stress, parental smoking, or alcohol consumption. The duration of symptomatic episodes was negatively associated with problem-focused coping, and positively related to avoidant coping. Hassle levels were elevated 3 weeks prior to symptom onset. These results indicate that the impact of life stress on vulnerability to infectious illness in children is moderated by psychological coping and social resources, and that different psychosocial factors influence the occurrence and duration of infections.

Introduction

There has been extensive study of the influence of psychosocial factors on infectious disease over recent years 1, 2. Evidence for links between psychosocial stress and susceptibility is particularly strong for upper respiratory infections, with associations being identified in viral challenge and in community-based studies 3, 4, 5, 6, 7. However, the majority of studies have been restricted to adults, and less is known about the role of psychosocial factors in children.

An early prospective study of 16 families showed that school-aged (6–15 years) children had higher rates of streptococcal infection and upper respiratory illness than younger children or adults [8]. Associations were also observed between infection and family stress, but adults and children were not differentiated in these analyses. A sample of 58 children (mean age 4.3 years, range 1–11 years) was monitored over a 1-year period by Boyce et al. [9], with regular clinical examinations and nasopharyngeal cultures for infections. The number of life events experienced over the year was associated with the duration of illness and severity of symptoms, but not with the occurrence of infectious illness. More recently, Boyce et al. [10] assessed 99 children aged 4.5–6 years, with parental reports of respiratory illness over a 12-week period. No association with life events experienced over the previous 12 months was observed in the sample overall, but the likelihood of illness increased with life events in children who showed the largest immunological responses to the challenge of entering kindergarten for the first time. Other studies have assessed psychosocial influences on infection in preschool children [11].

The evidence concerning psychosocial factors and upper respiratory infection in children is therefore somewhat inconclusive. Consequently, we carried out a 15-week prospective study with children aged 5–16 years, assessing the role of both major life events over the study period, and weekly hassles. Social support and psychological coping style were assessed as potential moderators of adverse experience, because these factors have been shown in other fields to affect the impact of life stress [12]. The analyses involved both between-subject comparisons of children who did and did not have an upper respiratory infection during the study period, and within-subject analyses of influences on the duration of illness episodes and their timing with respect to stressful experience. Previous studies indicate that the impact of stress on infection in children may be affected by age, gender, family structure, and socioeconomic status, so these were included as cofactors [9].

Two other issues that are of particular concern in naturalistic studies of upper respiratory infection are clinical verification and the role of negative affect [1]. Microbiological assays are difficult to incorporate into naturalistic studies because they involve regular invasive sampling for infectious agents or antibodies, together with culturing for a wide range of potential pathogens. However, psychological factors such as negative affectivity may influence the perception and reporting of symptoms independently of objective health status, so self-reports of infectious illness are open to bias [13]. In this study, we used objective verification of infectious episodes by clinical examination, and also included dysphoric mood as a covariate in analyses, so as to control for reporting biases. Because parents are likely to assist some children in psychological assessments, it is possible that their own psychological states might influence measures. We therefore also included measures of perceived stress in parents as cofactors in the analyses.