Childhood obstructive sleep apnoea ups risk of hypertension in adulthood

Results of the world’s first 10-year prospective longitudinal study on the natural history and long-term impact of childhood obstructive sleep apnoea (OSA) by investigators from the Chinese University of Hong Kong (CUHK) showed a 2.5-fold increase in risk of hypertension in adulthood in participants with vs without childhood OSA, potentially increasing the risk of cardio-cerebrovascular diseases in later life.

“Childhood OSA is often underdiagnosed despite its high prevalence. Snoring, night sweats and mouth breathing are the most common symptoms of OSA. Other symptoms include daytime inattention, hyperactivity, sleepiness and behavioural problems,” said Professor Albert Martin Li of the Department of Paediatrics, CUHK. “Medical attention should be sought for children found to have these symptoms. Paediatricians should routinely ask about symptoms of OSA in clinical practice.”

“Blood pressure [BP] follows a circadian rhythm and is 10–15 percent lower during sleep than wakefulness. OSA in both adults and children have been shown in previous studies to be associated with a relative increase in nocturnal BP,” said Dr Jun Chun-Ting Au of the Department of Paediatrics, CUHK.

“Results of our current study showed an independent association between childhood OSA and adulthood hypertension. Prompt diagnosis and early management of childhood OSA are therefore important in minimizing the risk of hypertension and cardio-cerebrovascular diseases later in life as well as reducing the associated healthcare burden,” said Dr Kate Ching-Ching Chan of the Department of Paediatrics, CUHK.

In the study, 243 participants (mean age at baseline, 9.8 years; male, 59 percent) with childhood OSA were recruited from a childhood OSA cohort (n=619) established in 2003–2005 for a childhood OSA epidemiology study. All participants received overnight polysomnography (PSG) and ambulatory BP monitoring at baseline and follow-up. [Thorax 2020;75:422-431]

At baseline, healthy controls, primary snorers and participants with mild and moderate-to-severe OSA accounted for 40.3 percent (n=98), 20.2 percent (n=49), 30.9 percent (n=75) and 8.6 percent (n=21) of the cohort, respectively. Participants with OSA had a significantly higher body mass index (BMI) (p=0.008) and higher prevalence of habitual snoring (p<0.001).

At a mean follow-up of 10.4 years, 63.7 percent and 11.5 percent of participants were healthy controls and primary snorers, while 16.5 percent and 8.2 percent had mild OSA and moderate-to-severe OSA, respectively.

Compared with controls, participants with childhood moderate-to-severe OSA at baseline had a significant 6.5 mm Hg increase in nocturnal systolic BP (SBP), a significant 4.1 percent reduction in nocturnal SBP dipping, as well as significantly increased risks of hypertension (relative risk [RR], 2.5; 95 percent confidence interval [CI], 1.2 to 5.3; p<0.05), nondipping of nocturnal SBP (RR, 1.3; 95 percent CI, 1.0 to 1.7; p<0.05) and increased mean arterial pressure (RR, 1.8; 95 percent CI, 1.3 to 2.4; p<0.001) at follow-up, after adjustment for sex, age, BMI, height and parental hypertension.

In addition, participants with vs without OSA at baseline had an 8.1 mm Hg increase in nocturnal SBP (p<0.001) and a 3.9 percent reduction in SBP nocturnal dipping (p<0.01) at follow-up, after multivariate adjustment.

“Our team plans to launch another 18- to 20-year longitudinal study to follow up on the long-term health impact of childhood OSA in the same cohort,” Chan added.