High incidence of respiratory disease in Australian infants despite low rate of maternal cigarette smoking

Abstract

Aim The burden of wheezing illnesses in Australian infants has not been documented since the success of initiatives to reduce maternal cigarette smoking. We aimed to determine the incidence of wheeze and related health‐care utilisation during the first year of life among a contemporary Australian birth cohort. Methods A birth cohort of 1074 infants was assembled between 2010 and 2013. Parents completed questionnaires periodically. Several non‐exclusive infant respiratory disease phenotypes were defined, including any wheeze, wheeze with shortness of breath and recurrent wheeze. Skin prick testing was performed to determine atopic wheeze. Health‐care utilisation for respiratory disease was determined from questionnaires and hospital medical records. Results Retention to 1 year was 840/1074 (83%). The incidence of any wheeze was 51.8% (95% confidence interval (CI) 48.3–55.2%), wheeze with shortness of breath 20.6% (95% CI 17.9–23.5), recurrent wheeze 19.4% (95% CI 16.8–22.2) and atopic wheeze 6% (95% CI 4.6–7.8). Respiratory illness resulted in primary health‐care utilisation in 82.2% (95% CI 79.3–84.8) of participants and hospital presentation in 8.8% (95% CI 7.2–10.6). Maternal smoking during pregnancy was uncommon (15.7%) and was not associated with wheeze or health resource utilisation. Male gender, familial atopy and asthma and smaller household size were associated with a higher incidence of wheeze. Conclusions The incidence of wheezing illness among Australian infants remains high despite relatively low rates of maternal smoking during pregnancy. The majority of the health‐care burden is borne by primary health‐care services. Further research is required to inform novel prevention strategies.

Prevalence and associated factors of wheeze in early infancy

“…Prior studies have found that boys are at higher risk for developing wheezes than girls 41 . Our results also showed that the male sex is an associated factor of wheeze.…”

Burden of infection in Australian infants

“…This may suggest that birth by caesarean section does not increase the incidence of infection but does increase the severity of infection, measured by hospitalisation. Very few infants in our cohort were exposed to tobacco smoke in the home, 13 and this homogeneity likely explains why we did not observe an association between passive smoke exposure and infection. We also did not find any evidence suggesting that the ALSPAC hygiene score, 14 measured at 12 months of life, was associated with incidence of infection.…”

“…We did not adjust for season as each child was followed for a complete year. We used inverse probability weighting to account for selection bias, as in previous studies of this cohort 8,13 . Regression models were reweighted to account for potential differential distribution of exposures between the inception cohort and non‐enrolled mothers.…”

Are wheezing, asthma and eczema in children associated with mother’s health during pregnancy? Evidence from an Australian birth cohort

“…Children may suffer from asthma morbidities due to exposure to environmental tobacco smoke or parental prenatal/postnatal smoking [ 42 ]. Although the rate of maternal cigarette smoking during pregnancy has decreased in the last decade in Australia [ 4 ], the evidence of the influence of smoking during pregnancy on childhood asthma persists [ 45 ]. However, few studies have investigated the number of cigarettes smoked during pregnancy and its effects on respiratory and allergic morbidities in their children [ 27 ].…”