Strachan DP. Hay fever, hygiene, and household size. BMJ. 1989;299(6710):1259–60.

PubMed 
PubMed Central 

Google Scholar
 

Perkin MR, Strachan DP. The hygiene hypothesis for allergy – conception and evolution. Front Allergy. 2022;3:1051368.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

Adlerberth I, Wold AE. Establishment of the gut microbiota in western infants. Acta Paediatr. 2009;98(2):229–38.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

Article 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 

Google Scholar
 

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.

PubMed 
PubMed Central 

Google Scholar