Sleep Apnea & Heart Risk: Poor Sleep Quality Impacts Non-Obese Patients

Sleep-disordered breathing (SDB), even in individuals without obesity, is linked to an increased risk of cardiovascular disease (CVD), according to a recent cross-sectional study. The research, conducted in China, highlights the importance of addressing sleep quality, particularly in non-obese individuals diagnosed with SDB.

Study Details and Findings

The study, utilizing data from two surveys conducted in 2021 and 2023 in the Guangdong province of China, involved 6,520 participants. Researchers assessed sleep patterns using a type IV sleep monitor and evaluated cardiovascular risk using China-PAR risk equations. A total of 1983 participants (30.4%) were diagnosed with SDB, while 277 (4.2%) were classified as obese. Interestingly, the incidence of SDB was notably higher in non-obese individuals (29.4%) compared to those with obesity (54.2%).

The data revealed a significant correlation between SDB and cardiovascular risk, even independent of obesity. Among individuals without obesity, those with SDB exhibited greater 10-year CVD risk, lifetime CVD risk, and a higher overall risk of CVD compared to those without SDB. Conversely, among individuals with SDB, those without obesity had a lower 10-year CVD risk, lifetime CVD risk, and high-risk CVD classification than those with obesity.

Specifically, 18.9% of individuals with SDB and without obesity were classified as having a high risk for CVD, compared to 28.2% of those with SDB and obesity (P = .021). This suggests that while obesity exacerbates CVD risk in the context of SDB, the presence of SDB alone is a significant risk factor, even in the absence of excess weight.

Sleep Quality as a Key Factor

The study delved deeper into the relationship between sleep quality and CVD risk within the non-obese SDB cohort. Researchers found that individuals with a high risk of CVD had worse subjective sleep quality, shorter sleep duration, lower habitual sleep efficiency, and increased sleep disturbance. These findings underscore the importance of considering sleep quality as a modifiable risk factor for CVD in this population.

Logistic regression analysis confirmed that habitual sleep efficiency and sleep disturbance were independently associated with a high risk of CVD in the non-obese SDB group. Specifically, individuals with a habitual sleep efficiency of 64% or less had a 152% increased probability of high CVD risk, while those reporting fairly bad sleep disturbance had a 109% increased probability compared to those with no sleep disturbance.

Implications for Treatment and Prevention

The study authors emphasize that interventions focused on improving sleep quality may be particularly beneficial for individuals with SDB who are not obese. This is a crucial finding, as treatment strategies for SDB often prioritize weight loss, which may not be applicable or effective for all patients. Addressing factors like sleep hygiene, sleep environment, and underlying sleep disorders could offer a valuable approach to reducing CVD risk in this often-overlooked population.

While the study did not explore specific interventions, the findings suggest that improving sleep efficiency and reducing sleep disturbance could have a significant impact on cardiovascular health. Further research is needed to identify the most effective strategies for achieving these goals.

Study Limitations

The researchers acknowledge several limitations to their study. The cross-sectional design prevents the establishment of causal relationships between SDB, sleep quality, and CVD risk. CVD risk was calculated using an equation rather than long-term follow-up data. Finally, the number of participants with SDB and obesity was relatively small, limiting the ability to draw definitive conclusions about this subgroup.

Despite these limitations, the study provides valuable insights into the complex relationship between SDB, obesity, sleep quality, and cardiovascular health. The findings highlight the importance of considering sleep quality as a key factor in the prevention and management of CVD, particularly in non-obese individuals with SDB.

Recent research from the Sleep Foundation emphasizes the link between sleep apnea and heart disease, noting that sleep apnea alone, with or without obesity, can increase the risk. This reinforces the need for comprehensive evaluation and management of sleep disorders in individuals at risk for cardiovascular disease.