The effect of smoking on cumulative damage in systemic lupus erythematosus: An incident cohort study

Environmental exposure to polycyclic aromatic hydrocarbons: An underestimated risk factor for systemic lupus erythematosus onset and progression

OBJECTIVE

To investigate the link between systemic lupus erythematosus (SLE) incidence and exposure to environmental polycyclic aromatic hydrocarbons (PAH).

METHODS

A case-control study (ChiCTR2000038187) involving 316 SLE patients and 851 healthy controls (HCs) was executed. Environmental exposure was assessed via a questionnaire, stratified by gender and age (females <35 and ≥35 years, males). Blood samples collected from 89 HCs, 85 inactive, and 95 active SLE patients were used to measure serum benzo[a]pyrene diol epoxide -albumin (BPDE-Alb) adducts and PAH concentrations, indicating long-term and short-term exposure respectively. Intergroup comparisons and statistical analyses were conducted using R version 4.3.1.

RESULTS

Diverse patterns were found in how environmental factors affect SLE onset across different demographics. Lifestyle exposure factors were found to be a stronger determinant of SLE onset than occupational exposure factors in women under 35. Indoor air pollution had a significant impact on SLE incidence, potentially comparable to outdoor air pollution. Lifestyle-related PAH exposure had a greater impact on SLE than occupational PAH exposure. PAH exposure levels progressively increase from HCs to inactive and active SLE patients. Active SLE patients show markedly higher BPDE-Alb levels than HCs.

CONCLUSIONS

Environmental PAH, particularly lifestyle-related, are significant, yet under-recognized, risk factors for SLE.

STATEMENT OF ENVIRONMENTAL IMPLICATION

We examined the relationship between exposure to environmental polycyclic aromatic hydrocarbons (PAH) and the incidence of systemic lupus erythematosus (SLE). PAH, prevalent in sources such as cigarette smoke, air pollution, and charred food, pose significant health hazards. This study is the first to investigate specific PAH exposure levels in SLE patients. We determined actual PAH exposure levels in both SLE patients and healthy individuals and indicated that long-term PAH exposure biomarker is more reliable for evaluating exposure in non-occupationally exposed groups like SLE, compared to short-term markers. These findings provide valuable insights for future research on similar non-occupationally exposed populations.

Sex and Racial Differences in Systemic Lupus Erythematosus Among US Adults in the All of Us Research Program

OBJECTIVE

Men with systemic lupus erythematosus (SLE) are an understudied population. The present study characterized differences between men and women with SLE.

METHODS

We examined cross-sectionally participants with SLE in the All of Us Research Program, a US cohort with a participant survey at enrollment (May 2018 to June 2022) and linked electronic health record (EHR) data. We described and compared characteristics of men and women with SLE encompassing disease manifestations and prescribed medications from EHR data and socioeconomic factors, including health literacy and health care access and utilization, from surveys. We reported racial variations stratified by sex.

RESULTS

Of 1,462 participants with SLE, 126 (9%) were male. Men reported lower educational attainment and less fatigue than women. Myocardial infarction was significantly more common in men. Men had significantly less confidence in completing medical forms than women and exhibited a trend toward requiring more help in reading health-related materials. Barriers to health care access and utilization were common in both men and women (40% versus 47%, respectively, reporting some reason for delay in care; P = 0.35). Women of race other than Black or African American or White more often reported delaying care due to cultural differences between patient and provider.

CONCLUSION

Our study demonstrated major clinical and health literacy differences in men and women with SLE. Socioeconomic factors were significant barriers to health care in both sexes. Our study suggests men have disproportionately poorer health literacy, which may exacerbate preexisting disparities. Further large prospective studies, focusing on recruiting men, are needed to better characterize racial differences in men with SLE.

Smoking associated with reduced odds of Sjögren's syndrome among rheumatoid arthritis patients

OBJECTIVE

The objective of this medical record review study is to define the association between smoking and Sjӧgren's syndrome (SS) in a large rheumatoid arthritis (RA) cohort.

METHODS

Electronic health records from a population-based cohort were screened for RA eligibility between 2005 and 2018. Inclusion criteria were age ≥ 18 years, two or more RA diagnoses, including two diagnoses by a rheumatologist, or positive rheumatoid factor or anti-cyclic citrullinated peptide (anti-CCP) antibody. The independent variable, smoking status, was defined as never, current, or past. The outcome, SS, was defined by two or more ICD-9 codes. Multivariable logistic regression was performed to determine odds ratios (ORs) of SS adjusted for age, sex, and race.

RESULTS

Among 1861 patients with RA identified for cohort inclusion, 1296 had a reported smoking status. Current smokers were younger and less likely to be female than never smokers. The adjusted OR of current compared to never smokers was negatively associated with SS [OR 0.20, 95% confidence interval (CI) 0.06-0.65]. Female sex and age were associated with SS (OR 2.70, 95% CI 1.18-6.14; OR 3.75, 95% CI 1.23-11.4).

CONCLUSION

We report that RA patients who currently smoke had 80% lower odds of SS. Age had a 3.7-fold association and female sex a 2.7-fold association with SS among RA patients. Our data suggest a negative correlation between current smoking and prevalent SS among RA patients. Prospective studies examining pack-year relationships or smoking cessation could further examine risk reduction and causality to follow-up our cross-sectional observational study.

Smoking associates with increased BAFF and decreased interferon-γ levels in patients with systemic lupus erythematosus

Objective

In SLE, smoking increases the burden of cutaneous disease and organ damage, and leads to premature mortality. However, the effect of smoking on disease manifestations and cytokine levels of patients with SLE is unclear. This study compared characteristics of patients with SLE across smoking status, and determined the association of smoking with serum cytokine levels.

Method

A cross-sectional study of patients with SLE (n=99) during a research visit in which smoking status was ascertained. Smoking status was compared across classification criteria (American College of Rheumatology Classification Criteria for SLE (ACR97)), disease activity (SLE Disease Activity Index), autoantibody levels, accrued damage (Systemic Lupus International Collaborating Clinics/ACR Damage Index), and circulating concentrations of serum interferon-gamma (IFN-γ), interleukin (IL)-1β, IL-4, IL-6, IL-10, IL-12, IL-17, B cell-activating factor (BAFF), tumour necrosis factor-alpha, transforming growth factor beta 1 (TGF-β1), macrophage inflammatory protein 1 alpha (MIP-1α), MIP-1β and monocyte chemoattractant protein 1. Linear regression models determined the association between smoking and cytokine levels, adjusting for age and sex, clinical characteristics (model 1), and anti-inflammatory (IL-4, IL-10 and TGF- β1) and regulatory (IL-1β) cytokines (model 2).

Results

Among patients with SLE (97.9% ANA+; mean 48.48 years old; 86.9% female; mean 10 years of disease duration), 35.4% (n=35 of 99) were smoking (an average of 7 cigarettes/day for 24 years). Smokers had increased odds of prevalent ACR97 malar rash (OR 3.40, 95% CI 1.23 to 9.34) and mucosal ulcers (OR 3.31, 95% CI 1.36 to 8.05). Smokers had more arthritis (OR 3.19, 95% CI 1.19 to 8.60), migraine (OR 2.82, 95% CI 1.07 to 7.44), Raynaud’s phenomenon (OR 5.15, 95% CI 1.95 to 13.56) and increased non-steroidal anti-inflammatory drug use (OR 6.88, 95% CI 1.99 to 23.72). Smoking associated with 27% increased BAFF levels (95% CI 6% to 48%) and 42% decreased IFN-γ levels (95% CI −79% to −5%) in model 2.

Conclusion

In patients with SLE, smoking independently associated with increased BAFF and decreased IFN-γ levels, and an increased frequency of arthritis, migraine and Raynaud’s phenomenon. Smoking cessation is advisable to reduce systemic inflammation, reduce disease activity and improve host defence.

Predictors of Smoking Cessation in Patients With Rheumatoid Arthritis in Two Cohorts: Most Predictive Health Care Factors

OBJECTIVE

Recognizing smoking as a risk factor for rheumatoid arthritis (RA) severity, the present study was undertaken to evaluate patient- and health care-level predictors of smoking cessation in patients with RA to guide implementation of smoking cessation interventions.

METHODS

Electronic health record data from 2 health systems were abstracted for patients with at least 2 International Classification of Disease diagnosis codes for RA between 2005 and 2016. Patients missing smoking statuses or with <6 months of follow-up were excluded. Multivariable logistic regression was used to determine predictors of smoking cessation.

RESULTS

Among 3,577 patients with RA, 507 smoked at baseline, and 29% quit over a median of 4.75 years. Black male patients, ages 40-59 years and enrolled in Medicaid, were significantly more likely to be baseline smokers; however, none of these factors predicted cessation. Instead, patients new to rheumatology care were 60% more likely to quit (adjusted odds ratio [OR_adj ] 1.60 [95% confidence interval (95% CI) 1.02-2.50]), and patients in the rural community health system were 66% more likely to quit (OR_adj 1.66 [95% CI 1.03-2.69]). Seropositive patients were 43% less likely to quit smoking (OR_adj 0.57 [95% CI 0.35-0.91]).

CONCLUSION

Health care factors, including health system and being new to rheumatology care, were more predictive of smoking cessation in patients with RA than patient sociodemographic factors, suggesting an important role for health system cessation efforts for patients with RA. Seropositive patients were less likely to quit and may particularly benefit from cessation support. Emphasizing smoking cessation with new or seropositive RA patients and leveraging health system interventions could improve smoking cessation and outcomes in RA.