A retrospective analysis of longitudinal changes in bone mineral content in cystic fibrosis.

BACKGROUND: We aimed to describe the longitudinal changes in bone mineral content and influencing factors, in children with cystic fibrosis (CF). METHODS: One hundred children (50 females) had dual X-ray absorptiometry (DXA) performed. Of these, 48 and 24 children had two to three scans, respectively over 10 years of follow-up. DXA data were expressed as lumbar spine bone mineral content standard deviation score (LSBMCSDS) adjusted for age, gender, ethnicity and bone area. Markers of disease, anthropometry and bone biochemistry were collected retrospectively. RESULTS: Baseline LSBMCSDS was >0.5 SDS in 13% children, between -0.5; 0.5 SDS, in 50% and ≤-0.5 in the remainder. Seventy-eight percent of the children who had baseline LSBMCSDS >-0.5, and 35% of the children with poor baseline (LSBMCSDS<-0.5), showed decreasing values in subsequent assessments. However, mean LS BMC SDS did not show a significant decline in subsequent assessments (-0.51; -0.64; -0.56; p=0.178). Lower forced expiratory volume in 1 s percent (FEV1%) low body mass index standard deviation scores (BMI SDS) and vitamin D were associated with reduction in BMC. CONCLUSIONS: Bone mineral content as assessed by DXA is sub-optimal and decreases with time in most children with CF and this study has highlighted parameters that can be addressed to improve bone health.

Cardiopulmonary exercise testing in children with cystic fibrosis: one centre's experience.

BACKGROUND: While exercise testing is increasingly used as a prognostic indicator in cystic fibrosis (CF), it is reported to be underused in UK CF centres, particularly in children. Here, we evaluated the cardiopulmonary exercise testing (CPET) results in children and young people with CF at CF annual review and its possible clinical value. METHOD: An observational study comparing CPET results using a cycle ergometer ramp test (peak oxygen uptake (Vo2peak)) and pulmonary function (forced expiratory volume in 1 s (FEV1)) was performed with body mass index (BMI) used as a disease severity marker. Data were identified from clinical case notes and our CF database. RESULTS: Thirty-eight children and young people (mean age 11±2.4, range 7-14 years; 17 males and 21 females) completed at least one CPET with 95% achieving technically satisfactory tests allowing measurement of Vo2peak. Mean Vo2peak was 107 ±17.6% predicted, range 74%-150% predicted, with 8% having a reduced Vo2peak of <85% of predicted. Mean FEV1 z-score was -0.77±1.24, range -4.42 to 2.24. We did not demonstrate a significant correlation between Vo2peak % predicted and FEV1 z-score (r=0.25, p=0.13), or between Vo2peak % predicted and BMI z-score (r=-0.05, p=0.77). Twenty-eight of 38 completed a second CPET the following year with 71% showing a decline in Vo2peak (mean decline of 8% of predicted value, equivalent to 3.8 mL/kg/min). CONCLUSION: CPET is feasible with 95% of children and young people achieving technically satisfactory assessments starting from age 7. In this group with relatively mild CF, mean Vo2peak was normal with no significant correlation between Vo2peak and FEV1 or BMI, as markers of disease severity. The majority demonstrated a normal Vo2peak. However, 71% showed a downward trend on repeat testing 12-18 months later.

Changing trends in sex specific prevalence rates for childhood asthma, eczema, and hay fever.

Numerous surveys of school-aged children have shown increasing asthma prevalence with a less publicized but noticeable change in the male to female ratio. We sought to confirm this change in the sex ratio in four questionnaire-based surveys and investigate possible explanations. Identical questionnaire surveys were performed in 1989 (n=3,390), 1994 (n=4,047), 1999 (n=3,540) and 2004 (n=1,920) in school-children aged 9-11 years. Over these 15 years the male to female ratio (M:F) significantly narrowed for wheeze (1.34 to 0.98:1 P < 0.0002), for asthma (1.74 to 1.02:1 P < 0.0001), for eczema (1.42:1 to 0.81:1 P < 0.0001) and for hay fever (1.46 to 0.93:1 P < 0.0001). The diagnosis of asthma in children with wheeze was more commonly made in boys in 1989 relative risk RR 1.32 (1.12, 1.56), even in those with accompanying eczema and/or hay fever RR 1.20 (0.99, 1.45). By 2004 this sex bias in diagnosis was no longer present, RR 1.01 (0.91, 1.12) for wheeze and 1.02 (0.85, 1.21) for those with wheeze and eczema and/or hay fever. From 1989 to 2004 no significant difference in sex distribution changes between older and younger children occurred, making secular trends in the onset of puberty in females an unlikely contributory factor. The disappearance of the bias to diagnose asthma in symptomatic males but not in females may be partly responsible for the narrowing of the sex ratio, but other factors such as those enhancing the expression of asthma and atopy in females may also be implicated.

A comparison of virus-associated and multi-trigger wheeze in school children.

To examine differences between virus-associated wheeze and wheeze associated with other triggers (multi-trigger wheeze) in elementary school children, we performed a cross-sectional school-based questionnaire study of 5,998 children mainly 7 to 12 years of age, with outliers 6 and 13 years of age. Using parent-completed questionnaires, we identified 522 children who wheezed only during upper respiratory tract infections (virus-associated wheeze), 1,186 children who wheezed on other occasions (multi-trigger wheeze), and 4,290 children with no wheeze. In comparison with children who had multi-trigger wheeze, children with virus-associated wheeze were more likely to be male, to be younger, and to have less frequent wheezy episodes. They were less likely to have night cough, shortness of breath or chest tightness, to have a personal or parental history of atopic disorders, to have a diagnosis of asthma, or to be receiving asthma treatment. Both types of wheeze were associated with social deprivation, a relationship that persisted after controlling for family smoking. Virus-associated wheeze is a common but diminishing problem in this age group, and the differences between virus-associated wheeze and multi-trigger wheeze already noted in pre-school children persist in this older age group.