medwireNews: Adhering to a healthy lifestyle, namely never smoking, moderate alcohol use, regular exercise, healthy BMI, and healthy diet, is associated with a significantly reduced risk for rheumatoid arthritis (RA) in women, show data from the Nurses’ Health Studies.
The findings also revealed that 34% of incident RA cases detected may have been prevented if all women had adhered to at least four of these five modifiable healthy lifestyle factors.
“This is an important message for the general population and in particular those at risk by virtue of family history,” write Karen Costenbader (Brigham and Women’s Hospital, Boston Massachusetts, USA) and co-authors in Arthritis Care & Research.
Costenbader and team used the healthy lifestyle index score (HLIS) to determine the impact of a healthy lifestyle on RA risk.
They created a binary variable (healthy/unhealthy) for each of the five HLIS components, defining healthy as:
- never smoking;
- moderate alcohol use (5–15 g, or approximately one drink, per day);
- healthy BMI (18.5–24.9 kg/m2);
- regular exercise (≥19 Metabolic Equivalent of Task-hours/week, or approximately 30 minutes of daily brisk walking); and
- healthy diet (top 40th percentile of the Alternative Healthy Eating Index).
The Nurses’ Health Study (NHS; 1986–2016) and NHSII (1991–2017) included 107,092 women, of whom 1219 developed RA during 4,467,751 person–years of follow-up (mean 24 years follow-up per participant). Among the RA cases, 776 (63.7%) were seropositive and 443 (36.3%) were seronegative.
After adjustment for potential confounders, the researchers observed that the overall risk for RA decreased by a significant 13% per unit increase in HLIS, corresponding to each healthy behavior adopted. For seropositive and seronegative RA the corresponding risk reductions were a significant 14% and 12%.
When the data were analyzed by individual HLIS categories, the team found that women who reported one healthy lifestyle characteristic had a similar RA risk to those with none, whereas the risk was a significant 58% lower for women who adhered to all five components.
Using population attributable risk (PAR) analysis, the researchers showed that having a healthy BMI, not smoking, and consuming alcohol in moderation may independently prevent 17.3%, 14.0%, and 10.2% of RA cases, respectively, whereas a healthy diet and physical activity had minimal independent effects on PAR in these women. Overall, the PAR for the five factors combined was 34.0%.
“Our finding that a high proportion (34%) of RA risk in the general female population is attributable to the confluence of modifiable lifestyle factors represents something of a paradigm shift in thinking about RA and autoimmune disease risk,” Costenbader et al remark.
They suggest: “Promotion of multiple healthy behaviors to minimize risk is an important message for the general population and in particular those at risk by virtue of family history.”
They also stress that “[t]he development of an effective lifestyle-based RA prevention interventions must address […] socioeconomic barriers to healthy lifestyle.”
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