Background Early-life vitamin D deficiency may impair immune system development contributing to allergy and asthma onset. Findings from prospective studies are inconsistent. Objective To examine whether maternal and child vitamin D levels are associated with allergic and asthma-related symptoms throughout childhood in a Spanish birth cohort. Methods 25-Hydroxyvitamin D-3 (25(OH)D-3) levels were measured in the serum of pregnant women (N = 2525) and children (N = 803). Information on allergic and asthma-related symptoms was obtained from repeated questionnaires from 1 to 9 years. Results A total of 19% of mothers and 24% of children had deficient 25(OH)D-3 levels (<20 ng/ml). Higher child 25(OH)D-3 levels at 4 years were associated with lower odds of atopic eczema from 4 to 9 years (adjusted odds ratio = 0.90; 95% CI = 0.84-0.97 per 5 ng/ml). Higher maternal and child 25(OH)D-3 levels were associated with a lower prevalence of late-onset wheezing at the limit of statistical significance (adjusted relative risk ratio (RRRadj) = 0.86; 95% CI = 0.74-1.00 and RRRadj = 0.76; 95% CI = 0.58-1.02 per 5 ng/ml, respectively). All the remaining associations were null. Conclusion Child 25(OH)D-3 levels at pre-school age are associated with a reduced odds of atopic eczema in later childhood and both maternal and child levels may reduce the prevalence of late-onset wheezing. Impact In this Spanish birth cohort, with a total of 19% of mothers and 24% of children with deficient levels of vitamin D, higher child vitamin D at 4 years of age was associated with reduced odds of atopic eczema up to 9 years. There was also some evidence that higher maternal and child vitamin D levels reduced the prevalence of late-onset wheezing. Although these findings need replication, they may imply optimal vitamin D levels at pre-school age to prevent atopic eczema.

Participatory research (PR) is on the rise. In Spain, PR is scarce in the field of health, although there is an increasing interest in the matter. A comprehensive understanding of the meanings and practical implications of “public participation” is essential to promote participation in health research. The aim of the study is to explore the discursive positions on PR among individuals with experience in participatory processes in different areas and how this understanding translates into practice. We conducted a critical discourse analysis of 21 individuals with experience in PR and participatory processes (13 women, 8 men), mainly from the field of health and other areas of knowledge. Sixteen were Spanish and the rest were from the United Kingdom (3), United States (1), and Canada (1). Interviews were conducted in person or by telephone. The fieldwork was conducted between March 2019 and November 2019. The dominant discourses on public participation are situated along two axes situated on a continuum: the purpose of public participation and how power should be distributed in public participation processes. The first is instrumental public participation, which sees participatory research as a tool to improve research results and focuses on institutional interests and power-decision making is hold by researchers and institutions. The second, is transformative public participation, with a focus on social change and an equitable sharing of decision-making power between the public and researchers. All discursive positions stated that they do not carry out specific strategies to include the most socially disadvantaged individuals or groups. A shift in the scientific approach about knowledge, along with time and resources, are required to move towards a more balanced power distribution in the processes involving the public.