People with asthma have significantly more health problems beyond the lungs, including higher rates of hypertension, diabetes, and autoimmune diseases, according to a study of 28,828 middle-aged adults in Sweden.
Researchers analyzed data from participants aged 50 to 64 who took part in a national project assessing cardiopulmonary health. Among them, 1,816 participants (6.3%) reported having current physician-diagnosed asthma. Compared with those without asthma (n = 27,012), this group had significantly higher rates of several extrapulmonary comorbidities.
After adjusting for age, sex, BMI, and smoking history, asthma was associated with 30% higher likelihood of hypertension (odds ratio [OR] = 1.30; 95% confidence interval [CI], 1.16–1.46) and 42% higher odds of diabetes (OR = 1.42; 95% CI, 1.16–1.75). The odds of hyperlipidemia were also elevated (OR = 1.20; 95% CI, 1.04–1.39), as were the odds of celiac disease (OR = 2.52; 95% CI, 1.61–3.95) and rheumatic disease (OR = 1.43; 95% CI, 1.16–1.78).
Asthma was also linked to elevated markers of systemic inflammation and glucose dysregulation. Mean levels of C-reactive protein (CRP), an inflammation marker, were higher in participants with asthma (2.53 mg/L) compared with those without (2.08 mg/L; P<.001). Mean hemoglobin A1c (HbA1c), which reflects average blood glucose levels, was also higher among individuals with asthma (37.1 mmol/mol vs 36.5 mmol/mol; P<.001).
“Our findings suggest that in middle-aged people, asthma is independently associated with common comorbidities such as hypertension, diabetes and rheumatic disease, as well as elevated CRP and blood glucose,” said Juan Wang from the Department of Medical Sciences, Respiratory-, Allergy- and Sleep Research, Uppsala University, Uppsala, Sweden.
The researchers also examined lung function, measured through spirometry, and found that reduced lung function was associated with greater risk of comorbidities in participants with asthma. A 10% decrease in predicted forced vital capacity (FVC) was associated with increased odds of hypertension (OR = 1.10; 95% CI, 1.01–1.19), diabetes (OR = 1.47; 95% CI, 1.26–1.71), and rheumatic disease (OR = 1.22; 95% CI, 1.05–1.42). Lower predicted forced expiratory volume in one second (FEV₁) was also linked to diabetes (OR = 1.27; 95% CI, 1.12–1.44).
Among asthma patients, lower FVC and FEV₁ were also significantly associated with higher CRP and HbA1c levels. For example, a 10% decrease in predicted FVC was associated with a higher CRP (β = –0.20; 95% CI, –0.36 to –0.04; P=.014) and a higher HbA1c (β = –0.39; 95% CI, –0.66 to –0.12; P=.005).
Researchers reported that in most cases, the comorbidities developed after the participants were diagnosed with asthma, based on age of onset data. This temporal sequence was observed for hypertension, diabetes, celiac disease, and rheumatic disease.
People with asthma were more likely to report respiratory symptoms, such as cough, wheezing, or phlegm, and had higher BMI and waist circumference compared to non-asthma participants. However, allergic rhinitis, chronic rhinosinusitis, and recent symptom exacerbations were not significantly associated with the comorbidities or biomarker levels.
While the study was cross-sectional and cannot prove causality, the findings suggest that middle-aged individuals with asthma may carry a greater burden of systemic inflammation and related chronic diseases. The associations were strongest among those with lower lung function, underscoring the potential link between pulmonary impairment and broader metabolic and autoimmune health risks.
The authors reported no conflicts of interest.
Source: BMJ Open Respiratory Research
