Search

Background: Short-chain fatty acids (SCFAs) are abundant bacterial metabolites in the gut, with immunomodulatory properties. Hence, they may influence allergy development. Previous studies have linked fecal SCFA pattern during infancy with allergy. However, the association of SCFAs to allergic outcomes in adolescence is not well established. Here, we examined how the fecal SCFA pattern at 1 year of age related to allergy at 13 years of age. Methods: Levels of 8 SCFAs in fecal samples collected at 1 year of age from 110 children were quantified using gas chromatography. The same individuals were evaluated at 13 years of age for allergic symptoms, allergy diagnosis and allergy medication by questionnaire, and for sensitization using skin prick test against egg, milk, fish, wheat and soy, cat, dog, horse, birch, and timothy grass. Results: The concentration of fecal valeric acid at 1 year of age was inversely associated with eczema at 13 years of age (OR 0.6, 95% CI: 0.4–1.0, p = 0.049) and showed a trend for inverse association with food allergy at 13 years of age (OR 0.6, 95% CI: 0.4–1.0, p = 0.057). In a sub-group analysis of children with eczema at 1 year of age, a higher concentration of fecal valeric acid was linked with reduced risk of their eczema remaining at 13 years of age (OR 0.2, 95% CI: 0.0–1.5), although this latter analysis did not reach statistical significance (p = 0.12). Conclusions: Our findings lend further support to the notion of early childhood as a critical period when allergy may be programmed via the gut microbiota. Higher levels of fecal valeric acid may be characteristic of a protective gut microbiota and/or actively contribute to protection from eczema and food allergy. [ABSTRACT FROM AUTHOR]

Mechanistic research suggests that lifestyle and environmental factors impact respiratory health across generations by epigenetic changes transmitted through male germ cells. Evidence from studies on humans is very limited.We investigated multigeneration causal associations to estimate the causal effects of tobacco smoking on lung function within the paternal line. We analysed data from 383 adult offspring (age 18-47 years; 52.0% female) and their 274 fathers, who had participated in the European Community Respiratory Health Survey (ECRHS)/Respiratory Health in Northern Europe, Spain and Australia (RHINESSA) generation study and had provided valid measures of pre-bronchodilator lung function. Two counterfactual-based, multilevel mediation models were developed with: paternal grandmothers' smoking in pregnancy and fathers' smoking initiation in prepuberty as exposures; fathers' forced expiratory volume in 1 s (FEV 1 ) and forced vital capacity (FVC), or FEV 1 /FVC z-scores as potential mediators (proxies of unobserved biological mechanisms that are true mediators); and offspring's FEV 1 and FVC, or FEV 1 /FVC z-scores as outcomes. All effects were summarised as differences (Δ) in expected z-scores related to fathers' and grandmothers' smoking history.Fathers' smoking initiation in prepuberty had a negative direct effect on both offspring's FEV 1 (Δz-score -0.36, 95% CI -0.63- -0.10) and FVC (-0.50, 95% CI -0.80- -0.20) compared with fathers' never smoking. Paternal grandmothers' smoking in pregnancy had a negative direct effect on fathers' FEV 1 /FVC (-0.57, 95% CI -1.09- -0.05) and a negative indirect effect on offspring's FEV 1 /FVC (-0.12, 95% CI -0.21- -0.03) compared with grandmothers' not smoking before fathers' birth nor during fathers' childhood.Fathers' smoking in prepuberty and paternal grandmothers' smoking in pregnancy may cause lower lung function in offspring. Our results support the concept that lifestyle-related exposures during these susceptibility periods influence the health of future generations., Competing Interests: Conflict of interest: S. Accordini has nothing to disclose. Conflict of interest: L. Calciano has nothing to disclose. Conflict of interest: A. Johannessen has nothing to disclose. Conflict of interest: B. Benediktsdóttir has nothing to disclose. Conflict of interest: R.J. Bertelsen has nothing to disclose. Conflict of interest: L. Bråbäck has nothing to disclose. Conflict of interest: S.C. Dharmage has nothing to disclose. Conflict of interest: B. Forsberg has nothing to disclose. Conflict of interest: F. Gómez Real has nothing to disclose. Conflict of interest: J.W. Holloway reports grants from the European Union's Horizon 2020 research and innovation programme, and from the Research Council of Norway, during the conduct of the study. Conflict of interest: M. Holm has nothing to disclose. Conflict of interest: C. Janson has nothing to disclose. Conflict of interest: N.O. Jõgi has nothing to disclose. Conflict of interest: R. Jõgi reports grants from the Estonian Research Council (personal research grant number 562), during the conduct of the study; personal fees for consultancy and lectures from GSK, Boehringer and Novartis, personal fees for travel/accommodation/meeting expenses from GSK and Boehringer, outside the submitted work. Conflict of interest: A. Malinovschi has nothing to disclose. Conflict of interest: A. Marcon has nothing to disclose. Conflict of interest: J. Martínez-Moratalla Rovira has nothing to disclose. Conflict of interest: J.L. Sánchez-Ramos has nothing to disclose. Conflict of interest: V. Schlünssen has nothing to disclose. Conflict of interest: K. Torén has nothing to disclose. Conflict of interest: D. Jarvis reports grants from the European Union, during the conduct of the study. Conflict of interest: C. Svanes has nothing to disclose., (Copyright ©The authors 2021.)