Approximately half of the risk of developing systemic lupus erythematosus (SLE) can be reduced by following a set of healthy lifestyle behaviors, according to a study published in Arthritis and Rheumatology.1
“The approach of studying multiple lifestyle factors together rather than individually provides a more pragmatic and holistic understanding of how lifestyle factors can affect risk of disease events,” investigators stated.
Both genetic factors and environmental exposures, such as medications, cigarette smoke, alcohol, obesity, and hormones have been previously linked to patients developing SLE. Additionally, smoking increases the risk of SLE for anti-double stranded DNA (dsDNA) antibodies, the more severe subtype of SLE.
Using data from the Nurses’ Health Study (NHS) and Nurses’ Health Study II (NHSII), a total of 185,962 women with 203 cases of SLE were observed. Of these cases, 96 were anti-dsDNA positive and 107 were anti-dsDNA negative. A total of 4,649,477 person-years of follow-up were evaluated, with investigators utilizing a healthy lifestyle index score (HLIS) measurement to determine the correlation between certain behaviors and the risk of developing SLE. Factors included diet, exercise, smoking, alcohol intake, and body mass index. The HLIS ranges from 0, the least healthy, to 5, the healthiest. This was calculated at baseline and every 2 years via comprehensive questionnaires.
If a patient was diagnosed with SLE, they were required to complete the connective tissue disease (CTD) Screening Questionnaire, which included specific questions about their symptoms. Anti-dsDNA status was determined by both medical record review and laboratory testing.
A sensitivity analysis was used to calculate SLE-specific HLIS based on SLE risk factors like smoking, BMI, and alcohol consumption, but omitting exercise and dietary choices.
Higher HLIS scores were associated with lower SLE risk (HR 0.81 [95%CI 0.71- 0.94]) as well as dsDNA positive SLE (HR 0.78 [95%CI 0.63-0.95]). Women with 4 or more healthy factors had the lowest risk overall (HR 0.42 [95%CI 0.25-0.70]) and dsDNA positive SLE (HR 0.35 [95%CI 0.17-0.75]) when compared with women who had 1 or fewer healthy behaviors.
SLE-specific HLIS results indicated that higher scores were associated with lower SLE risk (HR 0.75 [95%CI 0.64-0.88]), and both dsDNA positive and negative subtypes (HR 0.67 [95%CI 0.53-0.85]), HR 0.82 [95%CI 0.67-1.00], respectively).
The risk of developing SLE was reduced by 19% with every increase in HLIS. The risk of dsDNA positive SLE reduced 22% with the addition of each healthy behavior. Those with genetic risk factors may be able to reduce their risk of SLE diagnosis by almost 50% with adherence to healthy lifestyle behaviors.
The study was limited by demographics, which were mostly White, female nurses. Their lifestyle habits, therefore, may be different from that of other ethnic populations. Further, only a small number of SLE cases were observed, which limited examination of extreme categories. Incidence rates were significantly lower in the NHS and NHSII cohorts when compared with the rest of the US population. In future studies, investigators would like to examine more diverse populations, with younger women and more severe disease.
“We found an inverse association between a combination of healthy lifestyle behaviors and SLE risk, associated with nearly half of the population attributable risk,” investigators concluded. “Our findings have implications for SLE prevention and the promotion of multiple lifestyle behaviors to derive the greatest benefit. We also provided further insight into the pathogenesis of SLE as a greater than expected proportion of SLE risk may be attributable to modifiable lifestyle factors.”
Choi MY, Hahn J, Malspeis S, et al. A Combination of Healthy Lifestyle Behaviors Reduces Risk of Incident Systemic Lupus Erythematosus [published online ahead of print, 2021 Jul 27]. Arthritis Rheumatol. 2021;10.1002/art.41935. doi:10.1002/art.41935