The −174G/C and −572G/C Interleukin 6 Promoter Gene Polymorphisms in Mexican Patients with Rheumatoid Arthritis: A Case-Control Study

Table 1

Comparison in selected characteristics between patients with rheumatoid arthritis and healthy controls.

Characteristics	Cases with RA; 𝑛=137	Controls; 𝑛=102	𝑃
Age (years), mean ± SD	50±9	48±10	0.191
Females (%)	135 (98.5)	96 (94.1)	0.076
Serum IL-6 (pg/mL)	10.9±17.9	1.14±3.4	<0.001

Quantitative variables are expressed as means ± standard deviations (SD) and qualitative variables as frequencies and percentages (%) as noted. Abbreviations: RA: rheumatoid arthritis, IL-6: interleukin 6.
Comparisons between means were performed with unpaired Student’s t-test. Comparisons between proportions were performed with Chi-squared test.