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A healthy lifestyle before COVID-19 infection was associated with a substantially lower risk of a post-COVID condition (PCC), or long COVID, a prospective cohort study suggested.

Over 19 months of follow-up, women in the cohort who self-reported five to six healthy lifestyle factors -- healthy body mass index (BMI), never smoking, high-quality diet, moderate alcohol intake, regular exercise, and adequate sleep -- had a 49% lower risk of PCC compared with women with no healthy lifestyle factors (relative risk [RR] 0.51, 95% CI 0.33-0.78), reported Siwen Wang, MD, of Harvard T.H. Chan School of Public Health in Boston, and colleagues.

In a model adjusted for all lifestyle factors, those that were independently associated with risk of PCC were healthy BMI (18.5-24.9; RR 0.85, 95% CI 0.73-1.00, P=0.046) and adequate sleep (7-9 hours per night; RR 0.83, 95% CI 0.72-0.95, P=0.008), they noted in .

"The PAR [population attributable risk percentage] for all 6 healthy lifestyle factors in combination was 36.0%, indicating that, if these associations were causal, 36.0% of PCC cases would have been avoided if all participants had 5 or 6 healthy lifestyle factors prior to the pandemic," Wang and team wrote.

They noted that among the women who developed PCC, all COVID symptoms were less prevalent in those with higher healthy lifestyle scores, with the exception of smell/taste problems and headache (0-4 factors: mean number of symptoms 2.7; 5-6 factors: mean number of symptoms 2.3).

"Adherence to 5 to 6 versus 0 to 4 healthy lifestyle factors was associated with lower risk of daily life impairment due to PCC, although the CI was wide" (RR 0.70, 95% CI 0.44-1.12), they added.

Previous studies have shown that a combination of lifestyle factors had a dose-response association with lower risk of COVID and .

In the current study, Wang and colleagues said that several biological mechanisms may explain the observed associations.

"Sustained systemic inflammation has been implicated in the development of PCC," they wrote. "Chronic inflammation may predispose individuals to excessive release of cytokines after infection, subsequently increasing risk for long-term complications in multiple organs. Second, these unhealthy lifestyle factors dysregulate adaptive autoimmunity, which has been found in individuals with PCC."

"Future research should investigate whether lifestyle interventions may reduce risk of developing PCC or mitigate symptoms among individuals with PCC or possibly other postinfection syndromes," they concluded.

For this prospective cohort study, Wang and team included 1,981 women with a positive SARS-CoV-2 test from April 2020 to November 2021 from the Nurses' Health Study II. Mean age was 64.7 years, 97.4% were white, and 42.8% were active healthcare workers.

The participants reported pre-infection lifestyle habits in 2015 and 2017. Adequate exercise was defined as at least 150 minutes per week of moderate to vigorous physical activity, moderate alcohol intake was defined as 5 to 15 g per day (one drink contains about 10 g of alcohol), and a high-quality diet was defined as the upper 40% of Alternate Healthy Eating Index-2010 score.

COVID infections confirmed by test and PCC (at least 4 weeks of symptoms) were self-reported in seven surveys administered from April 2020 to November 2021.

PCC was reported in 44% of the cohort; 87% reported symptoms lasting at least 2 months, and 56.5% reported occasional daily life impairment.

The most commonly reported symptoms were fatigue (57.1%), smell or taste problems (40.9%), shortness of breath (25.3%), confusion/disorientation/brain fog (21.6%), and memory issues (20.0%).

The study is not generalizable to the general public, since it was conducted primarily in a population of white, middle-age female nurses, Wang and team noted. Although SARS-CoV-2 and PCC were self-reported, validity is likely high, given the population participating, they added

Importantly, less than 10% of participants had received their first COVID vaccine before becoming infected. A higher number of people are now vaccinated, and results may not be attributable to newer COVID strains.

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