5. Limitations
fibrosis
INFLAMMATION, OXIDATIVE STRESS, FIBROSIS
The investigated study population consisted of a relatively narrow age stratum. Therefore, it is not possible to extrapolate the results to other age groups.The study sample analysed in this report was of relatively small size. This increases the uncertainty of the obtained results. However, we think that the results are likely to be correct as they were validated by a two-step validation analysis. Nevertheless, based on the small sample size, we consider the results as hypothesis-generating.The evaluated population consisted of Caucasians who were low in selenium. The results might, therefore, not be applicable to other ethnicities or to selenium-replete populations.However, there are several important strengths of the main project, of which this sub-analysis is part.First, we supplemented an elderly, non-hospital-based population, where a follow-up was applied lasting up to 12 years. Secondly, the intervention was a prospective double-blind placebo-controlled randomised clinical trial. Thirdly, a long intervention time of 48 months was applied. Fourthly, in several sub-analyses, different perspectives of the effects of the intervention were applied, ranging from evaluation of expression of microRNA and telomere length, through to analyses of inflammation, oxidative stress and fibrosis, and also analysing health-related quality of life. To this framework, the presented sub-analysis adds important knowledge that indicates an effect on the ageing process in selenium-deficient individuals.