This study explores the relationship between socioeconomic position (SEP) across the life course and circulating C-reactive protein (CRP), a marker of systemic inflammation, in 6 European cohort studies participating in the Lifepath project. Methods: To evaluate the importance of the context and cohort specificities, analyses were performed separately for each cohort and combined in a random effect meta-analysis of up to 23 008 participants (55.7% of men). First, we estimated the association

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... ween measures of three time point SEP (father's occupation as early life SEP, educational attainment as young adulthood, participant's last occupation as adulthood) and adulthood CRP, adjusting for health behaviours (smoking, alcohol consumption, sedentary) and body mass index (BMI). Second, to mimic life course experiences, we analysed the relationship between father's occupation and CRP, sequentially adjusting for subsequent measures of SEP in young adulthood and adulthood on a subset of 4 cohort studies (N = 13 078). We also investigated whether health behaviours or BMI affected the association between life course SEP and inflammation. Results: Our findings reveal a consistent inverse association between SEP and CRP across cohorts, where participants with lower SEP had higher levels of CRP. In most cohorts, and in the meta-analysis, educational attainment was the SEP indicator most strongly related to inflammation where low educational attainment was associated with higher log-transformed levels of CRP ( = 0.30, 95% CI 0.22-0.38). Our findings also suggest that the higher CRP among the low educational attainment group was only partly attributable to BMI ( = 0.19, 95% CI 0.11-0.28) and smoking ( = 0.27, 95% CI 0.19-0.35). Conclusions: Socioeconomic circumstances across the life course are associated with higher levels of inflammation in adulthood, suggesting that social-to-biological processes are at play, beyond the impact of health behaviours and BMI. Key messages: Socioeconomic position across the lifecourse was associated with a higher level of inflammation in adults across six cohorts. Numerous social-to-biological processes and pathways are likely to be involved in the relationship observed between educational attainment and CRP in adult life, beyond behavioural factors. Background: The participation rates in health examination surveys have been declining, risking the representativeness of survey results. Information on the effectiveness of recruitment methods is needed to find cost-effective methods to increase the participation rates in future studies. The aim of the study was to examine whether a reminder increased participation among different socio-demographic groups. Methods: A nationally representative sample (n = 11,965) of subjects aged 18 or over were invited in the FinHealth 2017 Survey. After the invitation letter was sent, additional contacts (phone calls, postcards, SMS messages) to remind and motivate participation were made for those who did not confirm their appointment in two weeks. The comparisons between groups were made using X2 test and Z-test. Results: A total of 58.1% of the sample participated in health examination, but only half of them (28.8% of the sample) participated actively without a reminder. 8.27% of the sample returned only the questionnaire and 33.6% did not participate. Active participation in health examination was higher among women than men (34% vs. 24%), and among married persons (34.8%) and those who were at least 55 years old (17.1-40.6%) versus unmarried persons (23.0%) and age groups below 55 years (9.2-28.7%). Reminders and contacts increased participation especially among men, younger and unmarried subjects as well as those speaking some other language than Finnish. The increase was notable among the 18-24 years olds (9.2% for active participation vs. 27.6% for participation after a reminder). Conclusions: Additional contacts to remind and motivate participation were needed for half of those participating in health examination. Reminders and contacts were beneficial especially for younger and male subjects as well as those with restricted language skills. Key messages: Additional contacts to remind and motivate participation are needed in the recruitment process of a health examination survey. Participation rates can be improved e.g. by targeting recruitment efforts for specific population groups.