ИСТИНА

Background: Radiographic hand osteoarthritis (OA) is a frequent condition in any population, ranging in prevalence from 29 to 76%. The possible explanations for differences between populations are diverse genetic backgrounds and environmental exposure. Populations with exceptional numbers of long-lived individuals (longevity populations) were comprehensively studied. Studies performed on centenarians compared to older subjects (approximately 60 years old, when mortality rises dramatically, in order to avoid cohort effects) have reported that centenarians escape the major age-related diseases, with a minority still in good health. However, we found no studies of prevalence and severity of OA in longevity population. Because OA is associated with morbidity and mortality, we hypothesized that radiographic hand OA would generally be less prevalent and would develop at a later age in longevity populations versus non-longevity populations. Objectives: 1) to evaluate if prevalence and mode of development of radiographic hand osteoarthritis (OA) differs in three longevity populations (Abkhazians, Azerbaijanis and Georgians) and in one non-longevity population (Russians); 2) to evaluate if longevity of the population is associated with OA. Methods: Study design: Cross-sectional observational study. Sample: Data were collected by the Institute and Museum of Anthropology, Moscow University during several annual expeditions in eights decade of the last century. The aim of these expeditions was to collect data for the USSR countrywide study of environmental adaptation in humans. Longevity index (LI) was calculated as a ratio of the number of individuals aged >90 years versus the number of people aged >60, expressed in per mills (‰). OA was evaluated in 14 joints of the left hand according to Kellgren and Lawrence’s grading system. A diagnosis of OA was determined by the number of affected joints (NAJ) and by the presence of at least one affected joint. Statistical analyses included prevalence estimation, linear, logistic and polynomial regressions, and ANOVA. Results: Three sampled populations fulfilled the criterion for longevity populations (LI >40‰): the Abkhazians (LI=60-70‰), Azerbaijanis (LI=50-60‰) and Georgians (LI=40-50‰); and one sample was a non-longevity population: Russians (LI=10-20‰). A significant difference (p<0.003) in age standardized prevalence of hand OA was found between each pair of studied samples, except between the Russians and Georgians and between the Azerbaijanis and Abkhazians (p>0.05). The lowest age standardized prevalence was found in the Abkhazians followed by the Azerbaijanis and Georgians. The highest prevalence was found in the Russians. ANOVA showed significant differences (p<0.01) between the age-adjusted means of NAJs. The lowest age adjusted mean NAJ was found in the Abkhazian population followed by the Azerbaijanis and Georgians. The highest NAJ was found in the Russians. Conclusions: We observed that the pattern of radiographic hand OA in longevity populations differs from non-longevity populations. Results of our study indicate that longevity populations age slower than non-longevity populations. On average, first joints with OA appear at an older age and progression of hand OA, measured by NAJ, is slower. Keywords: longevity, ageing, osteoarthritis, hand, Kellgren and Lawrence’s grading system