Current smoking status was inversely associated with the development of primary Sjogren syndrome (pSS), suggesting that current smokers were less likely to be diagnosed with the condition, according to a population-based, retrospective cohort study published in The Journal of Rheumatology. In contrast, body mass index (BMI) and obesity have not demonstrated any relationship with pSS.
The investigators sought to explore the role played by smoking and obesity among individuals with pSS. A total of 106 Olmsted County, Minnesota, residents who had been diagnosed with pSS between January 1, 2000, and December 31, 2015, were compared with 3 age- and gender-matched controls without pSS (n=318).
Study results showed that current smokers were significantly less likely than participants who never smoked to have pSS (odds ratio [OR], 0.34; 95% CI, 0.14-0.85; P <.021). No association was reported, however, between former-smoker status and control status (OR, 1.27; 95% CI, 0.80-2.03) compared with never-smoker status.
Among the 106 patients with pSS, the following additional results were noted: 65% of participants who were current or former smokers (ever smokers) were positive for antinuclear antibodies, compared with 83% of those who never smoked (P =.06);72% of ever smokers were positive for SSA compared with 83% of never smokers (P =.16); 62% of ever smokers were positive for SSB compared with 60% of never smokers (P =.78); and 56% of ever smokers were positive for rheumatoid factor compared with 55% of never smokers (P =.92). With respect to obesity, the OR for pSS was 0.79 (95% CI, 0.48-1.30).
The major limitations of this study were related to its retrospective design. Data were not always systematically acquired, and the researchers note that it was not possible to conduct a precise quantification of current and prior smoking status or to analyze the temporality between current smoking status and onset of pSS symptoms among all participants.
The investigators concluded that although current smoking is inversely associated with control status, BMI lacks any such association. The mechanisms responsible for this association or lack of association are unknown.
Servioli L, Maciel G, Nannini C, et al. Association of smoking and obesity on the risk of developing primary Sjögren syndrome: a population-based cohort study [published online January 15, 2019]. J Rheumatol. doi: 10.3899/jrheum.180481