Older Sjögren’s patients may face more lung issues, study reports
Researchers call for broader studies to confirm findings
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People diagnosed with Sjögren’s disease at an older age may have more clinically recognized problems with their lungs than younger patients, a study found.
Due to incomplete data on potential influencing factors, further studies are needed to confirm these findings, researchers emphasized.
The study, “Clinical, serological, and hematological profiles according to age at diagnosis in primary Sjögren disease: a single-center cross-sectional study,” was published in Rheumatology International by a team of researchers in Turkey.
Lung involvement significantly more common in the late-age group
Sjögren’s, sometimes called primary Sjögren’s, is an autoimmune disease whose hallmark symptoms are dry eyes and a dry mouth. However, the disease can affect several other parts of the body and cause a wide range of symptoms. Many patients test positive for self-reactive antibodies that mistakenly attack healthy tissue, most commonly the anti-Ro (SS-A) and anti-La (SS-B) antibodies.
Previous studies have reported differences in symptoms, antibody status, and organ involvement, including of the lungs, between younger and older Sjögren’s patients.
Because Sjögren’s can manifest in different ways and begin gradually, “symptom onset and diagnostic delay may be difficult to determine retrospectively,” the researchers wrote. Therefore, “age at diagnosis may provide a pragmatic framework for describing clinical [variability].”
To understand whether the age at diagnosis could help describe differences between people with Sjögren’s, the team analyzed data from 258 Sjögren’s patients. These were divided into three groups according to age at diagnosis: 54 were diagnosed before age 40 (young adult group), 137 between ages 40 and 59 (middle-age group), and 67 at age 60 or older (late-age group).
Women were the majority in all three groups, although the proportion of women was significantly lower among patients diagnosed at age 60 or older compared with the other two groups (56.7% vs. 75.2% for the middle-age group and 77.8% for the young adult group).
When comparing clinical features, the researchers found that lung involvement was significantly more common in the late-age group relative to the other groups (28.4% vs. 5.1% and 3.7%, respectively).
Late-age group had more simultaneous conditions
Further analyses showed that being diagnosed at age 60 or older was significantly linked to an eight times higher chance of lung involvement compared with a diagnosis before age 40. No such link was found for the middle-age group.
This group showed a significantly lower frequency, by about half, of involvement outside the glands that produce tears and saliva compared with the two age extremes (16.8% vs. 31.5% for young adults and 35.8% for the late-age group).
Available smoking data showed a trend toward a higher proportion of current or previous smokers in the late-age group (41.4% vs. 16.7% for young adults and 23.9% for the middle-age group), but this difference failed to reach statistical significance, meaning it could be due to chance.
The late-age group also had more age-related comorbidities (simultaneous conditions), including chronic obstructive pulmonary disease, an inflammation of the lungs that can block the airways.
However, high-resolution chest imaging scans were not performed systematically on everyone, meaning that lung involvement may have been detected more often in older patients because they were more likely to undergo this type of scan, the team noted.
The overall Sjögren’s disease activity score, a measure of how active and severe the disease is, did not differ significantly between the three groups.
Multicenter studies [following patients over time] with systematic pulmonary assessment, complete smoking and comorbidity data, and information on symptom onset and diagnostic delay are needed to validate these findings.
Notably, anti-SSB/La antibodies were found significantly more often in patients diagnosed before age 40 (34%) than in those diagnosed between ages 40 and 59 (13.3%) or at age 60 or older (22.4%).
Blood levels of C-reactive protein (CRP), a marker of body-wide inflammation, was significantly higher in the two groups of patients diagnosed at an older age.
“Because age-related [coexisting conditions] were more frequent in older patients, CRP was interpreted as a non-specific inflammatory marker rather than a disease-specific biomarker,” the team wrote.
Red cell distribution width standard deviation, a measure of how much red blood cells vary in size, significantly increased with increasing age at diagnosis. In addition, some indexes of inflammatory activity differed significantly between the groups. However, all showed poor to modest ability to distinguish the groups.
Overall, this single-center study suggests that age at Sjögren’s diagnosis is associated with some differences, particularly in lung involvement and blood-based measures. Patients diagnosed at age 60 or older were more likely to have clinically recognized lung involvement, while younger patients were more likely to have anti-SSB/La antibodies.
Still, the association between older age at diagnosis and lung involvement “should be interpreted cautiously, because smoking exposure, age-related comorbidities, systematic [chest scan] screening, diagnostic pathway, disease duration, and symptom-to-diagnosis interval were incompletely captured,” the researchers wrote.
“Multicenter studies [following patients over time] with systematic pulmonary assessment, complete smoking and comorbidity data, and information on symptom onset and diagnostic delay are needed to validate these findings,” the team concluded.
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