Strachan DP. Hay fever, hygiene, and household size. BMJ. 1989;299(6710):1259–60.
Perkin MR, Strachan DP. The hygiene hypothesis for allergy – conception and evolution. Front Allergy. 2022;3:1051368.
Wang M, Karlsson C, Olsson C, Adlerberth I, Wold AE, Strachan DP, et al. Reduced diversity in the early fecal microbiota of infants with atopic eczema. J Allergy Clin Immunol. 2008;121(1):129–34.
Ismail IH, Oppedisano F, Joseph SJ, Boyle RJ, Licciardi PV, Robins-Browne RM, et al. Reduced gut microbial diversity in early life is associated with later development of eczema but not atopy in high-risk infants. Pediatr Allergy Immunol. 2012;23(7):674–81.
Abrahamsson TR, Jakobsson HE, Andersson AF, Björkstén B, Engstrand L, Jenmalm MC. Low diversity of the gut microbiota in infants with atopic eczema. J Allergy Clin Immunol. 2012;129(2):434–40, 40.e1-2.
Gao Y, Stokholm J, O’Hely M, Ponsonby AL, Tang MLK, Ranganathan S, et al. Gut microbiota maturity mediates the protective effect of siblings on food allergy. J Allergy Clin Immunol. 2023;152(3):667–75.
Depner M, Taft DH, Kirjavainen PV, Kalanetra KM, Karvonen AM, Peschel S, et al. Maturation of the gut microbiome during the first year of life contributes to the protective farm effect on childhood asthma. Nat Med. 2020;26(11):1766–75.
Adlerberth I, Wold AE. Establishment of the gut microbiota in western infants. Acta Paediatr. 2009;98(2):229–38.
Stewart CJ, Ajami NJ, O’Brien JL, Hutchinson DS, Smith DP, Wong MC, et al. Temporal development of the gut microbiome in early childhood from the TEDDY study. Nature. 2018;562(7728):583–8.
Adlerberth I, Strachan DP, Matricardi PM, Ahrne S, Orfei L, Aberg N, et al. Gut microbiota and development of atopic eczema in 3 European birth cohorts. J Allergy Clin Immunol. 2007;120(2):343–50.
Jangi S, Lamont JT. Asymptomatic colonization by Clostridium difficile in infants: implications for disease in later life. J Pediatr Gastroenterol Nutr. 2010;51(1):2–7.
Adlerberth I, Carlsson B, de Man P, Jalil F, Khan SR, Larsson P, et al. Intestinal colonization with Enterobacteriaceae in Pakistani and Swedish hospital-delivered infants. Acta Paediatr. 1991. https://doi.org/10.1111/j.1651-2227.1991.tb11917.x.
Stokholm J, Thorsen J, Chawes BL, Schjørring S, Krogfelt KA, Bønnelykke K, et al. Cesarean section changes neonatal gut colonization. J Allergy Clin Immunol. 2016;138(3):881-9.e2.
Dierikx TH, Visser DH, Benninga MA, van Kaam A, de Boer NKH, de Vries R, et al. The influence of prenatal and intrapartum antibiotics on intestinal microbiota colonisation in infants: a systematic review. J Infect. 2020;81(2):190–204.
Penders J, Gerhold K, Stobberingh EE, Thijs C, Zimmermann K, Lau S, et al. Establishment of the intestinal microbiota and its role for atopic dermatitis in early childhood. J Allergy Clin Immunol. 2013;132(3):601-7.e8.
Stokholm J, Blaser MJ, Thorsen J, Rasmussen MA, Waage J, Vinding RK, et al. Maturation of the gut microbiome and risk of asthma in childhood. Nat Commun. 2018;9(1):141.
Christensen ED, Hjelmsø MH, Thorsen J, Shah S, Redgwell T, Poulsen CE, et al. The developing airway and gut microbiota in early life is influenced by age of older siblings. Microbiome. 2022;10(1):106.
Laursen MF, Zachariassen G, Bahl MI, Bergstrom A, Host A, Michaelsen KF, et al. Having older siblings is associated with gut microbiota development during early childhood. BMC Microbiol. 2015;15:154.
Ljung A, Gio-Batta M, Hesselmar B, Imberg H, Rabe H, Nowrouzian FL, et al. Gut microbiota markers in early childhood are linked to farm living, pets in household and allergy. PLoS ONE. 2024;19(11): e0313078.
Lundell AC, Johansen S, Adlerberth I, Wold AE, Hesselmar B, Rudin A. High proportion of CD5+ B cells in infants predicts development of allergic disease. J Immunol. 2014;193(2):510–8.
Jonsson K, Barman M, Brekke HK, Hesselmar B, Johansen S, Sandberg AS, et al. Late introduction of fish and eggs is associated with increased risk of allergy development – results from the FARMFLORA birth cohort. Food Nutr Res. 2017;61(1): 1393306.
Adlerberth I, Lindberg E, Aberg N, Hesselmar B, Saalman R, Strannegård IL, et al. Reduced enterobacterial and increased staphylococcal colonization of the infantile bowel: an effect of hygienic lifestyle? Pediatr Res. 2006;59(1):96–101.
Ahrné S, Lönnermark E, Wold AE, Aberg N, Hesselmar B, Saalman R, et al. Lactobacilli in the intestinal microbiota of Swedish infants. Microbes Infect. 2005;7(11–12):1256–62.
Adlerberth I, Wold A, Hesselmar B. Data for: Major gut microbiota perturbations in firstborn infants compared to those with older siblings soon after delivery. University of Gothenburg; 2025. https://doi.org/10.5878/ea19-6s81.
Shao Y, Forster SC, Tsaliki E, Vervier K, Strang A, Simpson N, et al. Stunted microbiota and opportunistic pathogen colonization in caesarean-section birth. Nature. 2019;574(7776):117–21.
Bokulich NA, Chung J, Battaglia T, Henderson N, Jay M, Li H, et al. Antibiotics, birth mode, and diet shape microbiome maturation during early life. Sci Transl Med. 2016;8(343): 343ra82.
Barnett DJM, Endika MF, Klostermann CE, Gu F, Thijs C, Nauta A, et al. Human milk oligosaccharides, antimicrobial drugs, and the gut microbiota of term neonates: observations from the KOALA birth cohort study. Gut microbes. 2023;15(1):2164152.
Syed SA, Abrams GD, Freter R. Efficiency of various intestinal bacteria in assuming normal functions of enteric flora after association with germ-free mice. Infect Immun. 1970;2(4):376–86.
Albers LL, for the CNMDGa. The Duration of Labor in Healthy Women. J Perinatol. 1999;19(2):114–9.
Penders J, Thijs C, Vink C, Stelma FF, Snijders B, Kummeling I, et al. Factors influencing the composition of the intestinal microbiota in early infancy. Pediatrics. 2006;118(2):511–21.
Ismail IH, Boyle RJ, Licciardi PV, Oppedisano F, Lahtinen S, Robins-Browne RM, et al. Early gut colonization by Bifidobacterium breve and B. catenulatum differentially modulates eczema risk in children at high risk of developing allergic disease. Pediatr Allergy Immunol. 2016;27(8):838–46.
Martin R, Makino H, Cetinyurek Yavuz A, Ben-Amor K, Roelofs M, Ishikawa E, et al. Early-life events, including mode of delivery and type of feeding, siblings and gender, shape the developing gut microbiota. PLoS ONE. 2016;11(6): e0158498.
Lindberg E, Adlerberth I, Hesselmar B, Saalman R, Strannegård IL, Aberg N, et al. High rate of transfer of Staphylococcus aureus from parental skin to infant gut flora. J Clin Microbiol. 2004;42(2):530–4.
Lindberg E, Nowrouzian F, Adlerberth I, Wold AE. Long-time persistence of superantigen-producing Staphylococcus aureus strains in the intestinal microflora of healthy infants. Pediatr Res. 2000;48(6):741–7.
Lagier JC, Dubourg G, Million M, Cadoret F, Bilen M, Fenollar F, et al. Culturing the human microbiota and culturomics. Nat Rev Microbiol. 2018;16:540–50.
Vandeputte D, Kathagen G, D’Hoe K, Vieira-Silva S, Valles-Colomer M, Sabino J, et al. Quantitative microbiome profiling links gut community variation to microbial load. Nature. 2017;551(7681):507–11.
Jian C, Luukkonen P, Yki-Järvinen H, Salonen A, Korpela K. Quantitative PCR provides a simple and accessible method for quantitative microbiota profiling. PLoS ONE. 2020;15(1): e0227285.
Papathoma E, Triga M, Fouzas S, Dimitriou G. Cesarean section delivery and development of food allergy and atopic dermatitis in early childhood. Pediatr Allergy Immunol. 2016;27(4):419–24.
Pistiner M, Gold DR, Abdulkerim H, Hoffman E, Celedón JC. Birth by cesarean section, allergic rhinitis, and allergic sensitization among children with a parental history of atopy. J Allergy Clin Immunol. 2008;122(2):274–9.
Baron R, Taye M, der Vaart IB, Ujčič-Voortman J, Szajewska H, Seidell JC, et al. The relationship of prenatal antibiotic exposure and infant antibiotic administration with childhood allergies: a systematic review. BMC Pediatr. 2020;20(1):312.
Strombeck A, Nordstrom I, Andersson K, Andersson H, Johansen S, Maglio C, et al. Allergic disease in 8-year-old children is preceded by delayed B cell maturation. Clin Exp Allergy. 2017;47(7):918–28.
Lundell AC, Björnsson V, Ljung A, Ceder M, Johansen S, Lindhagen G, et al. Infant B cell memory differentiation and early gut bacterial colonization. J Immunol. 2012;188(9):4315–22.
Rabe H, Lundell AC, Sjoberg F, Ljung A, Strombeck A, Gio-Batta M, et al. Neonatal gut colonization by Bifidobacterium is associated with higher childhood cytokine responses. Gut microbes. 2020;12(1):1–14.
Gio-Batta M, Sjöberg F, Jonsson K, Barman M, Lundell AC, Adlerberth I, et al. Fecal short chain fatty acids in children living on farms and a link between valeric acid and protection from eczema. Sci Rep. 2020;10(1):22449.