Abdominal obesity, gender and the risk of rheumatoid arthritis – a nested case–control study

Abstract

BackgroundThe risk of development of rheumatoid arthritis (RA) could be affected by immune activation in obesity. Our objective was to evaluate the association between obesity in general, and abdominal obesity, and the risk for subsequent development of RA.MethodsIn two large population-based, prospective cohorts, 557 cases (mean age at RA symptom onset 58, SD 10 years, 68% women) who subsequently developed RA and 1671 matched controls were identified. From a health examination antedating symptom onset (median 5.5 years), collected data on body mass index (BMI; kg/m2), smoking habits, and educational level was used in conditional logistical regression models. Corresponding regression models were used to analyse the association between waist circumference measurements (cm) and RA development in a subset of the population.ResultsBMI and waist circumference were associated with the risk of RA development, adjusted odds ratio (OR) (95% CI), 1.13 (1.00, 1.28) per 5 kg/m2, and 1.02 (1.01, 1.04) per cm, respectively. An association was also observed for obesity (BMI ≥30) OR 1.45 (1.07, 1.95), compared with BMI <25. After stratification for sex the associations were enhanced in men, and attenuated in women. Among men with BMI above normal a 3–5 times increased risk for RA disease development at 50 years of age or earlier was observed. Abdominal obesity with waist circumference >102 cm was associated with a 2–3 times increased risk of RA, but not abdominal obesity (>88 cm) in women.ConclusionsObesity or abdominal obesity, respectively, was independently associated with a modest increase of the risk for subsequent development of RA. This appeared to be relevant mainly for early RA disease onset among men.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1171-2) contains supplementary material, which is available to authorized users.

Are obesity and rheumatoid arthritis interrelated?

“…Elevated body mass index, particularly caused by abdominal obesity, has been associated with a number of diseases and metabolic abnormalities, many of which have high morbidity and mortality . Over the last several decades, there have been several studies addressing the association between RA and obesity and investigating the added risk derived from being obese compared with the general population . The mechanism by which obesity may lead to RA is unidentified.…”

Genetic and environmental risk factors for rheumatoid arthritis

“…One study has shown that an increasing body mass index (BMI) was protective against RA development in men, although there was no significant relationship with RA risk in women (94). Another study showed that an increasing BMI was a risk factor for RA in both men and women, but less so in women (95). In addition, and in contrast to the above mentioned prospective study where obesity was a risk factor for progression to RA in ACPA(+) individuals (93), in another cohort of ACPA(+) individuals without baseline IA, Rakieh and colleagues found no significant relationship between a high BMI (>=25) and the development of future IA/RA (55).…”

Memory T cells specific to citrullinated α-enolase are enriched in the rheumatic joint

“…Other risk factors mainly for ACPA-positive RA include the intake of dietary salt in smokers, obesity, female sex, the exposure to air pollution and the inhalation of textile or silica dust, as mediated by an occupational exposure to these compounds [161][162][163][164][165]. Also, the exposure to infectious agents, such as specific bacteria and viruses has frequently been discussed as a possible trigger and driving factor of RA.…”