The cause of post-COVID-19 conditions, or “long COVID,” is the preeminent mystery of the COVID-19 pandemic. Defined as having COVID-19 symptoms for at least 4 weeks after acute infection, about 20-40% of infected persons develop long COVID.
Many long COVID questions have been investigated, often with mixed results: Why are young and healthy individuals susceptible? How effective are COVID-19 vaccines at preventing long COVID?
Because long COVID can manifest in a range of respiratory, cardiovascular, metabolic, gastrointestinal, neurological, and psychiatric symptoms, there is a need to identify any potential causes.
A new original investigation, published today in JAMA Internal Medicine, examined whether maintaining a healthy lifestyle prior to COVID-19 infection helped prevent post-COVID-19 conditions.
The longitudinal cohort study included 1981 female nurses living in the US. Participants were recruited from the Nurses’ Health Study II, which has been ongoing since 1989. Participants who met inclusion criteria were sent questionnaires regarding their health and lifestyle characteristics. During 19 months of follow-up, from April 2020-November 2021, participants reported any positive COVID-19 tests.
The investigators defined a “healthy lifestyle” as a healthy body mass index (BMI) between 18.5-24.9, a high-quality diet in the upper 40% of AHEI-2010 score, never smoking cigarettes, 7-9 hours of sleep a night, at least 150 minutes a week of moderate to vigorous exercise, and moderate alcohol consumption (5-15 g/d).
The primary objective was to determine the relative risk of post-COVID-19 conditions in association with the number of healthy lifestyle factors (0 to 6). Additionally, among the women who did develop post-COVID-19 conditions, the investigators examined whether a healthy lifestyle prior to acute infection was associated with the number of symptoms and symptom-related daily life impairments.
The average participant was 64.7 years old (range 55-75 years) and White (97.4%). Only 42.8% of the study patients (n = 848) were active health care workers. Of all 1981 women, 44% (n = 871) developed long COVID.
Healthy lifestyle choices were associated with a decreased risk of long COVID in a dose-dependent manner. It is notable, however, that the women with higher healthy lifestyle scores were more likely to be younger and White. They also had higher socioeconomic status and a lower prevalence of comorbidities.
Only 36 women fulfilled all 6 healthy lifestyle factors, leading the investigators to combine women with 5 or 6 factors in their analyses. Compared to women without any of the healthy lifestyle practices, the participants who exemplified 5-6 had a 49% lower risk of post-COVID-19 conditions.
In a model adjusted for all lifestyle factors, having a BMI of 18.5-24.9 and sleeping 7-9 hours a night were both independently associated with a statistically significant risk of post-COVID-19 conditions. The investigators determined that if these relationships were causal, 36.0% of long COVID cases would have been prevented if all participants employed 5-6 healthy lifestyle practices.
Among participants who developed post-COVID-19 conditions, all symptoms were less prevalent in women with higher healthy lifestyle scores, with the exceptions of smell or taste problems and headache. Practicing 5-6 healthy lifestyle choices compared to 0-4 was associated with a lower risk of daily life impairment due to long COVID.
The study authors concluded that living a healthy lifestyle prior to COVID-19 infection was correlated with a significantly lower risk of post-COVID-19 conditions. They recommended further research to determine whether lifestyle interventions can reduce the risk of developing long COVID or mitigate symptoms among individuals who do experience post-COVID-19 conditions.