FIGURE 2.
(A) Timepoint 1: birth. The associations between all measured microbial‐related early life factors and naïve and activated cord blood T regulatory cells as a proportion of CD4+ cells at birth (n = 463). Parental history of allergic disease: either parent has a history of allergic disease (asthma, eczema, hay fever, and food allergy), no otherwise. Parental ownership of livestock: family ownership of livestock in the prenatal period, no otherwise. Parental occupation: farm work—either parent has worked on a farm in the prenatal period, no otherwise. Maternal Antibiotic use in Trimester (T) 1/2/3: the mother took antibiotics during trimester 1, 2, or 3 (separate variables for each trimester), no otherwise. Pet dog ownership during pregnancy: presence of a household pet dog during the prenatal period, no otherwise. Pet cat ownership during pregnancy: presence of a household pet cat during the prenatal period, no otherwise. Any pet ownership during pregnancy: presence of any household pets, including dogs and cats during the prenatal period, no otherwise. Baby has four Caucasian grandparents: the child has all 4 Caucasian (British/Irish and European) grandparents, no otherwise. Mother positive for Group B Streptoccocus status: mother's GBS status at labour/birthwas positive, no otherwise. Number of siblings in T1&2: 1 or more siblings aged under 18 living in the home during T1T2, none otherwise. Household residents in T1&2: number of people of any age living at home in T1T2 is 3 or more, less otherwise. Household adult residents in T1&2: number of people aged over 18 years living in the home in T1T2 is 3 or more, less otherwise. Remoteness of location: lives in regional area or regional city, as the reference group. Maternal occupational social contact: levels Low, Medium, and High as outlined in 21 . Paternal occupational social contact: levels Low, Medium, and High as outlined in 21 . Disinfectant use in T1/2/3: values = none, <1 week, about 1 week, a few times per week, every day. (B). Timepoint 2: 6 months. The associations between microbial‐related early life factors and T regulatory cells as a proportion of CD4+ cells at 6 months of age (n = 600). Parental history of allergic disease: either parent has a history of allergic disease (asthma, eczema, hay fever, and food allergy), no otherwise. Parental ownership of livestock: ownership of livestock in the prenatal period, no otherwise. Parental occupation: farm work—either parent has worked on a farm in the prenatal period, no otherwise. Baby antibiotic use to 4 weeks: the baby took antibiotics in the first 4 weeks, no otherwise. Baby antibiotic use 4 weeks–3 months: the baby took antibiotics in the first 4 weeks–3 months, no otherwise. Baby antibiotic use 3–6 months: the baby took antibiotics in the first 3–6 months, no otherwise. Baby antibiotic use birth to 6 months: the baby took antibiotics between birth and 6 months, no otherwise. Pet dog ownership during infancy: presence of a household dog by 12‐month review, no otherwise. Pet cat ownership during infancy: presence of a household cat by 12‐month review, no otherwise. Baby has four Caucasian grandparents: the child has all four Caucasian (British/Irish and European) grandparents, no otherwise. Remoteness of location: lives in regional area or regional city, as the reference group. Number of siblings in T1&2: number of siblings aged under 18 living in the home during T1T2 is one or more, none otherwise. Household residents in T1&2: number of people of any age living at home in T1T2 is 3 or more, less otherwise. Household adult residents in T1&2: number of people aged over 18 years living in the home in T1T2 is 3 or more, less otherwise. Baby handwashing frequency at 4 weeks/6months: how often were baby's hands washed or wiped at 4 weeks and 6 months; three or more times/day compared to 2 times/day‐none at all. Maternal handwashing method at 4 weeks/6 months: Method of hand washing by the mother after changing baby's nappy at 4 weeks, and 6 months; wash hands with soap compared to don't clean hands, rinse with water only, wipe hands only, use a hand sanitizer. Maternal hand sanitizer use at 4 weeks/6 months: mother uses hand sanitizer after changing baby's nappy at 4 weeks, and 6 months, no otherwise. Baby bathing frequency at 4 weeks/6 months: how often baby is bathed; several times a week or once or more a day compared to once a week or less. Hygiene score at 6 months: baby's ALSPAC hygiene score at 6 months22. No. of continuous breastfeeding up to 6 months: the number of mothers who continuously breastfed their child up to 6 months. Breastfeeding duration: how long the mother breastfed for; any for 6 months or longer, breastmilk feeding at 1 week but not 6 months, no or stopped breastmilk feeding before 1 week. Maternal/Paternal occupational social contact: low or not elsewhere classified, medium, or high as per Ponsonby et al. 21 . (C). Timepoint 3: 12 months. The associations between microbial‐related early life factors and T regulatory cells as a proportion of CD4+ cells at 12 months of age (n = 675). Parental history of allergic disease: either parent has a history of allergic disease (asthma, eczema, hay fever, food allergy), no otherwise. Parental ownership of livestock: family ownership of livestock in the prenatal period, no otherwise. Parental occupation: farm work—either parent has worked on a farm in the prenatal period, no otherwise. Baby antibiotic use 6–12 months: the baby took antibiotics between 6 and 12 months, no otherwise. Baby has four Caucasian grandparents: the child has all 4 Caucasian (British/Irish and European) grandparents, no otherwise. Pet dog ownership during infancy: presence of a household dog by 12‐month review, no otherwise. Pet cat ownership during infancy: presence of a household cat by 12‐month review, no otherwise. Remoteness of location: lives in regional area or regional city, as the reference group. Number of siblings in T1&2: number of siblings aged under 18 living in the home during T1T2 is one or more, none otherwise. Household residents in T1&2: number of people of any age living at home in T1T2 is 3 or more, less otherwise Household adult residents in T1&2: number of people aged over 18 years living in the home in T1T2 is 3 or more, less otherwise. Baby handwashing frequency at 12 months: how often were baby's hands washed or wiped at 12 months; 3 or more times/day compared to 2 times/day‐none at all. Maternal handwashing method at 12 months: Method of hand washing by the mother after changing baby's nappy at 12 months; wash hands with soap compared to don't clean hands, rinse with water only, wipe hands only, use a hand sanitizer. Maternal hand sanitizer use at 12 months: mother uses hand sanitizer after changing baby's nappy at 12 months, no otherwise. Baby bathing frequency at 12 months: how often baby is bathed; several times a week or once or more a day compared to once a week or less. Hygiene score at 12 months: baby's ALSPAC hygiene score at 12 months 22 . Continuous breastfeeding to 12 months: baby was breastfed up to 12 months. Any formal childcare in first 12 months: baby received any regularly scheduled formal childcare in a childcare center in the first 12 months, no otherwise. Maternal/Paternal occupational social contact: low or not elsewhere classified, medium 21