Latitude gradient influences the age of onset in rheumatoid arthritis patients

Abstract

The mean age of rheumatoid arthritis (RA) onset is around 50 years as reported in several clinical trials involving Caucasian patients. However, clinical observations suggest that Mexican RA patients' disease is initiated at a younger age. The objective of the study was to assess whether the age of onset of RA is different in Mexican and in Canadian RA patients. Certified rheumatologists from Canada and Mexico directly interviewed consecutive RA patients attending their clinics regarding the date patients first noticed a swollen joint. None of the participant rheumatologists were aware of the primary aim of this exploratory study at the time of the interviews. Data was gathered from 161 Mexican (91% women) and 130 Canadian (77% women) RA patients collected by three rheumatologists in each country. Duration since disease onset was not different within countries (mean 95% confidence interval [CI] for differences -10 to 16 years, p = 0.12 for Canadians, and -6 to 10 years, p = 0.26, for Mexicans). However, there was a significant difference between the two countries. Mexicans patients on average developed RA almost 12 years younger than Canadians (95% CI for difference 9 to 15 years, p< 0.001). Frequency distribution showed that 35.5% of Canadians but only 4% of Mexicans had the onset of the disease after the age of 55 (all p < 0.001). It appears that RA begins at a much younger age in Mexican than Canadian patients. If this were confirmed after controlling for different confounders and biases, it would have important societal, economic, and therapeutic implications.

Active Rheumatoid Arthritis in Central Africa: A Comparative Study Between Sudan and Sweden

“…This finding agrees with another north-south comparative study between a developing and an industrialized country, showing that Canadian patients with RA also had a higher age of onset compared with patients with RA from Mexico 22 . We hypothesized that our finding might be secondary to the fact that Swedes have a 20-year longer life expectancy than Sudanese 23 .…”

Type I Interferon Gene Response Is Increased in Early and Established Rheumatoid Arthritis and Correlates with Autoantibody Production

“…Other diseases such as periodontal disease and gingivitis associated with several bacterial species such as PAD-like-producing Porphyromonas gingivalis have been speculated to increase the availability of citrullinated antigens and therefore the probability of autoantibody generations against such antigens (8). Differences in age for the onset of RA and its symptoms have been proposed to be not only due to the exposure to UV radiation (9) but also due to pesticides, in both the domestic and work environments altering some mechanisms of the oxidative stress response and contributing to tissue damage and RA initiation (10). …”

Fifteen-year trend in information on the World Wide Web for patients with rheumatoid arthritis: evolving, but opportunities for improvement remain

“…To assess the accessibility of relevant web pages, we examined the order of appearance of the hits in the search retrieval and categorized the results (10 web hits per page excluding declared paid adds) as follows: First corresponds to the first 20 hits; second for hits 21-100 (pages 3-10); third for hits 101-200 (for pages [11][12][13][14][15][16][17][18][19][20], and fourth for hits 201-300 (pages 21-30).…”

“…Although the incidence of RA peaks during the fifth decade of life, in some countries, the disease begins before age 35 in almost half of patients [16]. This means that the disease may last for decades.…”