New research uncovers how obesity amplifies long COVID risks and why smoking’s impact may be limited to memory problems, providing fresh insights into post-COVID health challenges.
Study: Influence of smoking and obesity on post-COVID-19 sequelae and risk of hospitalization. Image Credit: Kateryna Kon / Shutterstock
In a recent study published in the journal Frontiers in Medicine, researchers in Spain investigated the effects of smoking and obesity on post-coronavirus disease 2019 (COVID-19) sequelae and hospitalization risk.
The COVID-19 pandemic has significantly impacted global healthcare systems. It mainly affects the respiratory system, and its symptoms manifest within one to two weeks. Further, there are concerns about persistent symptoms lingering for weeks or months following the initial COVID-19 diagnosis, a phenomenon termed long COVID. These symptoms may last for years, with some patients experiencing ongoing health impacts more than two years post-diagnosis.
Long COVID symptoms include fatigue, difficulty concentrating, memory loss, loss of smell/taste, and headache, among others. Obesity has been considered a risk factor for severe outcomes in COVID-19. Likewise, smoking is a significant risk factor for respiratory diseases, including COVID-19. However, there is limited evidence about the impact of obesity and smoking on the development of long COVID symptoms and associated risks.
About the study
In the present study, researchers investigated the effects of smoking and obesity on post-COVID-19 sequelae and hospitalization risk. The study population included COVID-19 patients confirmed through polymerase chain reaction (PCR) tests in November 2020 in the Castilla y León region of Spain. Eligible participants were former or current smokers and overweight/obese individuals (body mass index > 25 kg/m2).
In addition, a control group was established comprising individuals who were not smokers and not obese/overweight. Information on the risk of hospitalization within 12 months post-COVID-19 diagnosis was also required for inclusion. Individuals with a history of chronic conditions, such as dyslipidemia, hypertension, or diabetes, before COVID-19 were excluded.
The researchers obtained data on participants’ age, gender, cardiovascular disease status, long COVID sequelae, memory loss, memory disorders, chronic conditions, and hospitalization. Women represented a higher proportion of participants in all groups: 59.9% of the obesity group, 56.3% of the smoking group, and 54.3% of the control group. Descriptive statistics were used to characterize the sample. Odds ratios were calculated to examine the relationship of obesity and smoking with post-COVID-19 sequelae, cardiovascular disease, chronic conditions (hypertension, dyslipidemia, and diabetes), and hospitalization risk.
Findings
In total, the smoking, obesity, and control groups included 918, 1,285, and 14,216 subjects, aged 42.6, 34.3, and 36.3 years, on average, respectively. The most common sequelae following COVID-19 infection were cough, myalgia, headache, changes in taste/smell, and fatigue, observed in 1.34% of smokers, 3.42% of obese subjects, and 1.8% of controls.
Memory disorders occurred in 0.98% of smokers, 1.1% of obese patients, and 0.42% of controls. Further, there was no statistically significant association between obesity status and the presence of chronic conditions or between smoking history and the presence of post-COVID-19 sequelae. By contrast, there was a significant association between obesity and post-COVID-19 sequelae.
Furthermore, the team identified potential interactions between smoking and obesity in the development of post-COVID-19 sequelae, suggesting that patients with a history of smoking and obesity may have a higher risk of these sequelae. A significant association was observed between smoking history and memory disorders, indicating that patients who smoke may be at a greater risk of experiencing memory disorders post-COVID-19.
Similarly, there was a significant association between obesity and memory disorders, suggesting obesity may elevate the risk of memory disorders following COVID-19. Notably, there were no significant interactions between smoking, memory disorders, and obesity, suggesting they were independent of each other. Additionally, the researchers found no significant relationship between obesity and the risk of hospitalization.
A comparative analysis between patients with obesity and smoking showed a higher risk of long COVID sequelae in overweight/obese individuals compared to smokers. Odds ratio analysis revealed that obese patients were 1.9 times more likely to develop long COVID sequelae than non-obese patients and had a 1.11 times greater risk of memory disorders than smokers. Further, patients who smoke and those with obesity had about 2.65 and 2.38 times higher risk of memory disorders and memory loss than non-smokers and non-obese patients, respectively.
Conclusions
Taken together, 1.9% of the cohort presented cardiovascular sequelae, and 1.31% showed long COVID sequelae. The findings suggest that smokers had no higher risk of long COVID sequelae than non-smokers, challenging prior studies suggesting a link between smoking and long COVID. Notably, obese patients had a higher risk of experiencing long COVID symptoms. However, contrary to previous findings, obesity did not increase the risk of hospitalization within 12 months post-COVID-19.
