Placental human papillomavirus infections and adverse pregnancy outcomes.

INTRODUCTION: Knowledge on prevalence and association of human papillomavirus (HPV) in third trimester placentae and adverse pregnancy outcomes is limited. We investigated the prevalence of placental HPV at delivery, explored urine HPV characteristics associated with placental HPV and whether placental HPV increased the risk adverse pregnancy outcomes. METHODS: Pregnant women were enrolled in the Scandinavian PreventADALL mother-child cohort study at midgestation. Human papillomavirus genotyping was performed on placental biopsies collected at delivery (n = 587) and first-void urine at midgestation and delivery (n = 556). Maternal characteristics were collected by questionnaires at gestational week 18 and 34. Adverse pregnancy outcomes were registered from chart data including hypertensive disorders of pregnancy, gestational diabetes mellitus and newborns small for gestational age. Uni- and multivariable regression models were used to investigate associations. RESULTS: Placental HPV was detected in 18/587 (3 %). Twenty-eight genotypes were identified among the 214/556 (38 %) with midgestational urine HPV. Seventeen of the 18 women with placental HPV were midgestational HPV positive with 89 % genotype concordance. Midgestational high-risk-(HR)-HPV and high viral loads of Any- or HR-HPV were associated with placental HPV. Persisting HPV infection from midgestation to delivery was not associated with placental HPV. Adverse pregnancy outcomes were seen in 2/556 (0.4 %) of women with placental HPV. DISCUSSION: In this general cohort of pregnant women, the prevalence of placental HPV was 3 %, and midgestational urinary HPV 38 %. High HPV viral load increased the risk for placental HPV infections. We observed no increased risk for adverse pregnancy outcomes in women with placental HPV.

Frequent oil-baths and skin barrier during infancy in the PreventADALL study.

BACKGROUND: In the general population randomized controlled PreventADALL trial, frequent emollient bath additives from 2 weeks of age did not prevent atopic dermatitis, while the effect on skin barrier function throughout infancy is not established. OBJECTIVE: The primary aim of this exploratory substudy was to assess the effect of mineral based oil-baths on transepidermal water loss (TEWL) and dry skin through infancy, and secondarily to explore if filaggrin (FLG) mutations modified the effect. METHODS: Overall 2153 infants randomized to Skin intervention (SI)(n=995) (oil-bath 4 times/week from 2 weeks through 8 months) or No skin intervention (NSI)(n=1158) with TEWL measurements at 3, 6 and/or 12 months of age were included, of whom 1683 infants also had available FLG mutation status. Effects of the skin intervention on TEWL and dry skin through infancy were assessed by mixed effects regression modelling. Background characteristics and protocol adherence were collected from electronic questionnaires, birth records and weekly diaries. RESULTS: The TEWL (95% CI) was in average 0.42 g/m2/h (0.13-0.70, p= 0.004) higher in the SI compared to NSI group through the first year of life, with significantly higher levels at 3 months, (8.6 (8.3-9.0) versus 7.6 (7.3-7.9)), but similar at 6 and 12 months. Dry skin was significantly more often observed in the NSI group compared to the SI group at 3 months (59% versus 51%) and at 6 months of age (63% versus 53%), while at 12 months of age, the difference was no longer significant. At 3 months, the TEWL of FLG mutation carriers was similar to the TEWL in SI group. No interaction between skin intervention and FLG mutation was found in the first year of life. CONCLUSIONS: Infants with frequent oil-baths from 2 weeks of age had reduced skin barrier function through infancy compared to controls, largely attributed to higher TEWL at 3 months of age, while the skin at 3 and 6 months appeared less dry in infants subjected to the skin intervention.

Infant lung function and early skin barrier impairment in the development of asthma at age 3 years.

BACKGROUND: Largely unexplored, we investigated if lower lung function, impaired skin barrier function by transepidermal water loss (TEWL), eczema, and filaggrin (FLG) mutations in infancy were associated with asthma in early childhood. METHODS: From the factorially designed randomized controlled intervention study PreventADALL, we evaluated 1337/2394 children from all randomization groups with information on asthma at age 3 years, and at age 3 months either lung function, TEWL, eczema, and/or FLG mutations. Lower lung function was defined as the time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) <0.25, and skin barrier impairment as a high TEWL >9.50 g/m2 /h. Eczema was clinically observed, and DNA genotyped for FLG mutations. Asthma was defined as asthma-like symptoms (≥3 episodes of bronchial obstruction) between age 2-3 years as well as a history of doctor-diagnosed asthma and/or asthma medication use. Associations were analyzed in logistic regression models, presented with adjusted ORs (aOR) and 95% confidence intervals (CI). RESULTS: Lower lung function and skin barrier impairment were associated with asthma in general; aOR (95% CI) 5.4 (2.1, 13.7) and 1.6 (1.1, 2.5), while eczema and FLG mutations were associated with asthma in children with atopic dermatitis or allergic sensitization only. Stratifying for sex, the risk of asthma was only increased in boys with lower lung function; aOR (95% CI) 7.7 (2.5, 23.6), and in girls with FLG mutations; aOR (95% CI) 3.5 (1.5, 8.2). CONCLUSION: Lower lung function and impaired skin barrier function in infancy may increase the risk of asthma at age 3 years.

Birth mode is associated with development of atopic dermatitis in infancy and early childhood.

Background: Birth by caesarean section (CS) is associated with development of allergic diseases, but its role in the development of atopic dermatitis (AD) is less convincing. Objective: Our primary aim was to determine if birth mode was associated with AD in 3-year-olds and secondarily to determine if birth mode was associated with early onset and/or persistent AD in the first 3 years of life. Methods: We included 2129 mother-child pairs from the Scandinavian population-based prospective PreventADALL cohort with information on birth mode including vaginal birth, either traditional (81.3%) or in water (4.0%), and CS before (6.3%) and after (8.5%) onset of labor. We defined early onset AD as eczema at 3 months and AD diagnosis by 3 years of age. Persistent AD was defined as eczema both in the first year and at 3 years of age, together with an AD diagnosis by 3 years of age. Results: AD was diagnosed at 3, 6, 12, 24, and/or 36 months in 531 children (25%). Compared to vaginal delivery, CS was overall associated with increased odds of AD by 3 years of age, with adjusted odds ratio (95% confidence interval) of 1.33 (1.02-1.74), and higher odds of early onset AD (1.63, 1.06-2.48). The highest odds for early onset AD were observed in infants born by CS after onset of labor (1.83, 1.09-3.07). Birth mode was not associated with persistent AD. Conclusion: CS was associated with increased odds of AD by 3 years of age, particularly in infants presenting with eczema at 3 months of age.

Eosinophil-derived neurotoxin levels in early childhood and association with preschool asthma - A prospective observational study.

INTRODUCTION: Eosinophil-derived neurotoxin (EDN) is related to childhood asthma, while normal values are lacking. We aimed to document serum EDN levels at 1 and 3 years in general and in non-atopic children, and explore if EDN levels differed by sex or were associated with preschool asthma at 3 years. METHODS: From the PreventADALL birth cohort, we included 1233 children with EDN analysed using ImmunoCAP at 1 and/or 3 years. Non-atopic children had no history of wheeze, asthma, allergic sensitization or atopic dermatitis. Preschool asthma was defined as having ≥3 episodes of bronchial obstruction between 2 and 3 years, plus doctor diagnosed asthma and/or asthma medication use by 3 years. The upper limit of normal (ULN) of EDN was defined as the 95th percentile. With Youden Index we calculated EDN cut-off levels for risk of preschool asthma. RESULTS: The overall median (ULN) EDN levels were 27.4 (121) µg/L at 1 year (n = 787), and 20.1 (87.8) µg/L at 3 years (n = 857). Non-atopic children had EDN levels of 24.0 (107) µg/L at 1 year (n = 147), and 17.3 (84.6) µg/L at 3 years (n = 173). EDN levels were higher in boys compared to girls; 32.0 (133) versus 24.5 (97.0) µg/L at 1 year, and 20.9 (96.3) versus 19.0 (72.4) µg/L at 3 years. Preschool asthma was observed in 109/892 (12.2%) children. Higher EDN levels at 1 (>26.7 µg/L) and 3 (≥20.5 µg/L) years were associated with preschool asthma; adjusted OR (95% CI) 2.20 (1.09, 4.41) and 4.68 (2.29, 9.55), respectively. CONCLUSION AND CLINICAL RELEVANCE: We report EDN values in early childhood, demonstrating higher levels at 1 compared to 3 years and in boys compared to girls at both ages. Higher EDN levels at both ages were associated with preschool asthma. However, EDN cut-off levels for preschool asthma were overall lower than the ULN of non-atopic children, limiting translation into clinical practice.

A Globally Distributed Bacteroides caccae Strain Is the Most Prevalent Mother-Child Shared Bacteroidaceae Strain in a Large Scandinavian Cohort.

Bacteroides and Phocaeicola, members of the family Bacteroidaceae, are among the first microbes to colonize the human infant gut. While it is known that these microbes can be transmitted from mother to child, our understanding of the specific strains that are shared and potentially transmitted is limited. In this study, we aimed to investigate the shared strains of Bacteroides and Phocaeicola in mothers and their infants. We analyzed fecal samples from pregnant woman recruited at 18 weeks of gestation from the PreventADALL study, as well as offspring samples from early infancy, including skin swab samples taken within 10 min after birth, the first available fecal sample (meconium), and fecal samples at 3 months of age. We screened 464 meconium samples for Bacteroidaceae, with subsequent selection of 144 mother-child pairs for longitudinal analysis, based on the presence of Bacteroidaceae, longitudinal sample availability, and delivery mode. Our results showed that Bacteroidaceae members were mainly detected in samples from vaginally delivered infants. We identified high prevalences of Phocaeicola vulgatus, Phocaeicola dorei, Bacteroides caccae, and Bacteroides thetaiotaomicron in mothers and vaginally born infants. However, at the strain level, we observed high prevalences of only two strains: a B. caccae strain and a P. vulgatus strain. Notably, the B. caccae strain was identified as a novel component of mother-child shared strains, and its high prevalence was also observed in publicly available metagenomes worldwide. Our findings suggest that mode of delivery may play a role in shaping the early colonization of the infant gut microbiota, in particular the colonization of Bacteroidaceae members. IMPORTANCE Our study provides evidence that Bacteroidaceae strains present on infants' skin within 10 min after birth, in meconium samples, and in fecal samples at 3 months of age in vaginally delivered infants are shared with their mothers. Using strain resolution analyses, we identified two strains, belonging to Bacteroides caccae and Phocaeicola vulgatus, as shared between mothers and their infants. Interestingly, the B. caccae strain showed a high prevalence worldwide, while the P. vulgatus strain was less common. Our findings also showed that vaginal delivery was associated with early colonization of Bacteroidaceae members, whereas cesarean section delivery was associated with delayed colonization. Given the potential for these microbes to influence the colonic environment, our results suggest that understanding the bacterial-host relationship at the strain level may have implications for infant health and development later in life.

Fetal pulmonary artery Doppler blood flow velocity measures and early infant lung function. A prospective cohort study.

BACKGROUND: Reduced lung function at birth has evident antenatal origins and is associated with an increased risk of wheezing and asthma later in life. Little is known about whether blood flow in the fetal pulmonary artery, may impact postnatal lung function. OBJECTIVE: Our primary aim was to investigate the potential associations between fetal Doppler blood flow velocity measures in the fetal branch pulmonary artery, and infant lung function by tidal flow-volume (TFV) loops at three months of age in a low-risk population. Our secondary aim was to explore the association between Doppler blood flow velocity measures in the umbilical and middle cerebral arteries, and the same lung function measures. METHODS: In 256 non-selected pregnancies from the birth cohort study Preventing Atopic Dermatitis and ALLergies in Children (PreventADALL) we performed fetal ultrasound examination with Doppler blood flow velocity measurements at 30 gestational weeks (GW). We recorded the pulsatility index, peak systolic velocity, time-averaged maximum velocity, acceleration time/ejection time ratio, and time velocity integral primarily in the proximal pulmonary artery close to the pulmonary bifurcation. The pulsatility index was measured in the umbilical and middle cerebral arteries and the peak systolic velocity in the middle cerebral artery. The cerebro-placental ratio (ratio between pulsatility index in the middle cerebral and umbilical arteries) was calculated. Infant lung function was assessed using TFV loops in awake, calmly breathing three months old infants. The outcome was the time to peak tidal expiratory flow to expiratory time ratio (tPTEF/tE), tPTEF/tE <25th percentile, and tidal volume per kg body weight (VT/kg). Potential associations between fetal Doppler blood flow velocity measures and infant lung function were assessed using linear and logistic regressions. RESULTS: The infants were born at median (min - max) 40.3 (35.6 - 42.4) GW, with a mean (SD) birth weight of 3.52 (0.46) kg, and 49.4% were females. The mean (SD) tPTEF/tE was 0.39 (0.1) and the 25th percentile was 0.33. Neither univariable nor multivariable regression models revealed any associations between fetal pulmonary blood flow velocity measures and tPTEF/tE, tPTEF/tE <25th percentile, or VT/kg at three months of age. Similarly, we did not observe associations between Doppler blood flow velocity measures in the umbilical and middle cerebral arteries and infant lung function measures. CONCLUSION: In a cohort of 256 infants from the general population, fetal third-trimester Doppler blood flow velocity measures in the branch pulmonary, umbilical, and middle cerebral arteries were not associated with infant lung function measures at three months of age.

Third trimester fetal lung volume, thoracic circumference, and early infant lung function.

BACKGROUND: We aimed to investigate the relationship between fetal third trimester lung volume (LV), thoracic circumference (TC), fetal weight, as well as fetal thoracic and weight growth, and early infant lung function. METHODS: Fetal LV, TC and estimated weight were measured with ultrasound at 30 gestational weeks in 257 fetuses from the general population-based prospective cohort study Preventing Atopic Dermatitis and ALLergies in Children (PreventADALL). Fetal thoracic growth rate and weight increase were calculated using TC and estimated fetal weight measured by ultrasound during pregnancy, and TC and birthweight of the newborn. Lung function was assessed by tidal flow-volume measurement in awake infants at 3 months of age. The associations between fetal size (LV, TC, and estimated weight) and growth (thoracic growth rate and fetal weight increase) measures and the time to peak tidal expiratory flow to expiratory time ratio (tPTEF /tE ) as well as tidal volume standardized for body weight (VT /kg) were analyzed using linear and logistic regression models. RESULTS: We observed no associations between fetal LV, TC or estimated fetal weight and tPTEF /tE as a continuous variable, tPTEF /tE < 25th percentile, or VT /kg. Similarly, fetal thoracic growth and weight increase were not associated with infant lung function. Analyses stratified for sex showed a significant inverse association between fetal weight increase and VT /kg (p = 0.02) in girls. CONCLUSION: Overall, fetal third trimester LV, TC, estimated fetal weight, thoracic growth rate and weight increase were not associated with infant lung function at 3 months of age.

The skin microbiome in the first year of life and its association with atopic dermatitis.

BACKGROUND: Early-life microbial colonization of the skin may modulate the immune system and impact the development of atopic dermatitis (AD) and allergic diseases later in life. To address this question, we assessed the association between the skin microbiome and AD, skin barrier integrity and allergic diseases in the first year of life. We further explored the evolution of the skin microbiome with age and its possible determinants, including delivery mode. METHODS: Skin microbiome was sampled from the lateral upper arm on the first day of life, and at 3, 6, and 12 months of age. Bacterial communities were assessed by 16S rRNA gene amplicon sequencing in 346 infants from the PreventADALL population-based birth cohort study, representing 970 samples. Clinical investigations included skin examination and skin barrier function measured as trans-epidermal water loss (TEWL) at the site and time of microbiome sampling at 3, 6, and 12 months. Parental background information was recorded in electronic questionnaires, and delivery mode (including vaginal delivery (VD), VD in water, elective caesarean section (CS) and emergency CS) was obtained from maternal hospital charts. RESULTS: Strong temporal variations in skin bacterial community composition were found in the first year of life, with distinct patterns associated with different ages. Confirming our hypothesis, skin bacterial community composition in the first year of life was associated with skin barrier integrity and later onsets of AD. Delivery mode had a strong impact on the microbiome composition at birth, with each mode leading to distinct patterns of colonization. Other possible determinants of the skin microbiome were identified, including environmental and parental factors as well as breastfeeding. CONCLUSION: Skin microbiome composition during infancy is defined by age, transiently influenced by delivery mode as well as environmental, parental factors and breastfeeding. The microbiome is also associated with skin barrier integrity and the onset of AD.

Maternal food-avoidance diets and dietary supplements during breastfeeding.

AIMS: To identify maternal food-avoidance diets and dietary supplement use during breastfeeding, and to explore factors associated with food avoidance diets. DESIGN: A prospective mother-child birth cohort study. METHODS: Electronic questionnaires were answered by 1,462 breastfeeding mothers 6 months postpartum in the Preventing Atopic Dermatitis and Allergies in Children (PreventADALL) study from 2014-2016. Demographic and antenatal factors were analysed for associations with food avoidance diets in 1,368 women by multiple logistic regression. RESULTS: Overall, 289 breastfeeding women (19.8%) avoided at least one food item in their diet, most commonly cow's milk in 99 women (6.8%). Foods were most often avoided due to conditions in the child, maternal factors or lifestyle choice. The odds for food avoidance diets were 2.1 (95% CI: 1.3, 3.4) for food allergy (presumed or diagnosed) and 19.4 (5.4, 70.1) for celiac disease in the mother. Dietary supplements were reported by nearly 80%, most commonly cod liver oil.

Fetal thoracic circumference in mid-pregnancy and infant lung function.

BACKGROUND AND AIM: Impaired lung function in early infancy is associated with later wheeze and asthma, while fetal thoracic circumference (TC) predicts severity of neonatal lung hypoplasia. Exploring fetal origins of lung function in infancy, we aimed to determine if fetal TC in mid-pregnancy was associated with infant lung function. METHODS: From the prospective Scandinavian general population-based PreventADALL mother-child birth cohort, all 851 3-month-old infants with tidal flow-volume measurements in the awake state and ultrasound fetal size measures at 18 (min-max 16-22) weeks gestational age were included. Associations between fetal TC and time to peak tidal expiratory flow to expiratory time (tPTEF /tE ) were analyzed in linear regression models. To account for gestational age variation, we adjusted TC for simultaneously measured general fetal size, by head circumference (TC/HC), abdominal circumference (TC/AC), and femur length (TC/FL). Multivariable models were adjusted for maternal age, maternal asthma, pre-pregnancy body mass index, parity, nicotine exposure in utero, and infant sex. RESULTS: The infants (47.8% girls) were born at mean (SD) gestational age of 40.2 (1.30) weeks. The mean (SD) tPTEF /tE  was 0.39 (0.08). The mean (SD) TC/HC was 0.75 (0.04), TC/AC 0.87 (0.04), and TC/FL 4.17 (0.26), respectively. Neither TC/HC nor TC/AC were associated with infant tPTEF /tE while a week inverse association was observed between TC/FL and tPTEF /tE  ( ß ^ $\hat{\beta }$ = -0.03, 95% confidence interval [-0.05, -0.007], p = 0.01). CONCLUSION: Mid-pregnancy fetal TC adjusted for fetal head or abdominal size was not associated with tPTEF /tE in healthy, awake 3-month-old infants, while a weak association was observed adjusting for fetal femur length.

Skin care interventions in infants for preventing eczema and food allergy.

BACKGROUND: Eczema and food allergy are common health conditions that usually begin in early childhood and often occur in the same people. They can be associated with an impaired skin barrier in early infancy. It is unclear whether trying to prevent or reverse an impaired skin barrier soon after birth is effective for preventing eczema or food allergy. OBJECTIVES: Primary objective To assess the effects of skin care interventions such as emollients for primary prevention of eczema and food allergy in infants. Secondary objective To identify features of study populations such as age, hereditary risk, and adherence to interventions that are associated with the greatest treatment benefit or harm for both eczema and food allergy. SEARCH METHODS: We performed an updated search of the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, and Embase in September 2021. We searched two trials registers in July 2021. We checked the reference lists of included studies and relevant systematic reviews, and scanned conference proceedings to identify further references to relevant randomised controlled trials (RCTs).  SELECTION CRITERIA: We included RCTs of skin care interventions that could potentially enhance skin barrier function, reduce dryness, or reduce subclinical inflammation in healthy term (> 37 weeks) infants (≤ 12 months) without pre-existing eczema, food allergy, or other skin condition. Eligible comparisons were standard care in the locality or no treatment. Types of skin care interventions could include moisturisers/emollients; bathing products; advice regarding reducing soap exposure and bathing frequency; and use of water softeners. No minimum follow-up was required. DATA COLLECTION AND ANALYSIS: This is a prospective individual participant data (IPD) meta-analysis. We used standard Cochrane methodological procedures, and primary analyses used the IPD dataset. Primary outcomes were cumulative incidence of eczema and cumulative incidence of immunoglobulin (Ig)E-mediated food allergy by one to three years, both measured at the closest available time point to two years. Secondary outcomes included adverse events during the intervention period; eczema severity (clinician-assessed); parent report of eczema severity; time to onset of eczema; parent report of immediate food allergy; and allergic sensitisation to food or inhalant allergen. MAIN RESULTS: We identified 33 RCTs comprising 25,827 participants. Of these, 17 studies randomising 5823 participants reported information on one or more outcomes specified in this review.  We included 11 studies, randomising 5217 participants, in one or more meta-analyses (range 2 to 9 studies per individual meta-analysis), with 10 of these studies providing IPD; the remaining 6 studies were included in the narrative results only.   Most studies were conducted at children's hospitals. Twenty-five studies, including all those contributing data to meta-analyses, randomised newborns up to age three weeks to receive a skin care intervention or standard infant skin care. Eight of the 11 studies contributing to meta-analyses recruited infants at high risk of developing eczema or food allergy, although the definition of high risk varied between studies. Durations of intervention and follow-up ranged from 24 hours to three years. All interventions were compared against no skin care intervention or local standard care. Of the 17 studies that reported information on our prespecified outcomes, 13 assessed emollients. We assessed most of the evidence in the review as low certainty and had some concerns about risk of bias. A rating of some concerns was most often due to lack of blinding of outcome assessors or significant missing data, which could have impacted outcome measurement but was judged unlikely to have done so. We assessed the evidence for the primary food allergy outcome as high risk of bias due to the inclusion of only one trial, where findings varied based on different assumptions about missing data. Skin care interventions during infancy probably do not change the risk of eczema by one to three years of age (risk ratio (RR) 1.03, 95% confidence interval (CI) 0.81 to 1.31; risk difference 5 more cases per 1000 infants, 95% CI 28 less to 47 more; moderate-certainty evidence; 3075 participants, 7 trials) or time to onset of eczema (hazard ratio 0.86, 95% CI 0.65 to 1.14; moderate-certainty evidence; 3349 participants, 9 trials). Skin care interventions during infancy may increase the risk of IgE-mediated food allergy by one to three years of age (RR 2.53, 95% CI 0.99 to 6.49; low-certainty evidence; 976 participants, 1 trial) but may not change risk of allergic sensitisation to a food allergen by age one to three years (RR 1.05, 95% CI 0.64 to 1.71; low-certainty evidence; 1794 participants, 3 trials). Skin care interventions during infancy may slightly increase risk of parent report of immediate reaction to a common food allergen at two years (RR 1.27, 95% CI 1.00 to 1.61; low-certainty evidence; 1171 participants, 1 trial); however, this was only seen for cow's milk, and may be unreliable due to over-reporting of milk allergy in infants. Skin care interventions during infancy probably increase risk of skin infection over the intervention period (RR 1.33, 95% CI 1.01 to 1.75; risk difference 17 more cases per 1000 infants, 95% CI one more to 38 more; moderate-certainty evidence; 2728 participants, 6 trials) and may increase the risk of infant slippage over the intervention period (RR 1.42, 95% CI 0.67 to 2.99; low-certainty evidence; 2538 participants, 4 trials) and stinging/allergic reactions to moisturisers (RR 2.24, 95% 0.67 to 7.43; low-certainty evidence; 343 participants, 4 trials), although CIs for slippages and stinging/allergic reactions were wide and include the possibility of no effect or reduced risk. Preplanned subgroup analyses showed that the effects of interventions were not influenced by age, duration of intervention, hereditary risk, filaggrin (FLG) mutation, chromosome 11 intergenic variant rs2212434, or classification of intervention type for risk of developing eczema. We could not evaluate these effects on risk of food allergy. Evidence was insufficient to show whether adherence to interventions influenced the relationship between skin care interventions and eczema or food allergy development. AUTHORS' CONCLUSIONS: Based on low- to moderate-certainty evidence, skin care interventions such as emollients during the first year of life in healthy infants are probably not effective for preventing eczema; may increase risk of food allergy; and probably increase risk of skin infection. Further study is needed to understand whether different approaches to infant skin care might prevent eczema or food allergy.

Infant lung function and maternal physical activity in the first half of pregnancy.

Background and aim: Physical activity (PA) in pregnancy is important for maternal and possibly offspring health. To study the early origins of lung function we aimed to determine whether PA in the first half of pregnancy is associated with lung function in healthy 3-month-old infants. Methods: From the general population-based Preventing Atopic Dermatitis and Allergies in Children birth cohort recruiting infants antenatally in Norway and Sweden, all 812 infants (48.8% girls) with available tidal flow-volume measures in the awake state at 3 months of age and mid-pregnancy data on PA were included. PA was self-reported by the mothers and, based on intensity, we categorised them as active or inactive during pregnancy. Furthermore, we defined active mothers as fairly or highly active. The main outcome was a ratio of time to peak tidal expiratory flow to expiratory time (t PTEF/t E) <0.25. Associations were analysed by logistic regression, adjusting for maternal age, education, parity, pre-pregnancy body mass index, in utero nicotine exposure and parental atopy. Results: The mean±sd t PTEF/t E was 0.391±0.08 and did not differ significantly according to maternal PA level in pregnancy. The 290 infants of inactive mothers had higher odds of having t PTEF/t E <0.25 compared to infants of all active mothers (OR 2.07, 95% CI 1.13-3.82; p=0.019) and compared to infants (n=224) of fairly active (OR 2.83, 95% CI 1.26-7.24; p=0.018) but not highly active mothers (n=298). Conclusion: Based on self-reported maternal PA in the first half of pregnancy, 3-month-old infants of inactive compared to active mothers had higher odds of a low t PTEF/t E.

Infant tidal flow-volume parameters and arousal state.

Background: Infant lung function can be assessed with tidal flow-volume (TFV) loops. While TFV loops can be measured in both awake and sleeping infants, the influence of arousal state in early infancy is not established. The aim of the present study was to determine whether TFV loop parameters in healthy infants differed while awake compared to the sleeping state at 3 months of age. Methods: From the population-based Scandinavian Preventing Atopic Dermatitis and ALLergies in children (PreventADALL) birth cohort, 91 infants had reproducible TFV loops measured with Exhalyzer® D in both the awake and sleeping state at 3 months of age. The TFV loops were manually selected according to a standardised procedure. The ratio of time to peak tidal expiratory flow (t PTEF) to expiratory time (t E) and the corresponding volume ratio (V PTEF/V E), as well as tidal volume (V T) and respiratory rate were compared using nonparametric tests. Results: The mean (95% CI) t PTEF/t E was significantly higher while awake compared to the sleeping state: 0.39 (0.37-0.41) versus 0.28 (0.27-0.29); with the corresponding V PTEF/V E of 0.38 (0.36-0.40) versus 0.29 (0.28-0.30). The V T was similar, while the respiratory rate was higher while awake compared to the sleeping state: 53 (51-56) breaths·min-1 versus 38 (36-40) breaths·min-1. Conclusion: Higher t PTEF/t E, V PTEF/V E and respiratory rate, but similar V T while awake compared to the sleeping state suggests that separate normative TFV loop values according to arousal state may be required in early infancy.

Infant lung function: criteria for selecting tidal flow-volume loops.

Background: Tidal flow-volume (TFV) loops are commonly recorded in infants during sleep, due to the more regular breathing patterns compared to the awake state. Standardised deselection of loops outside pre-specified ranges are based on periods of regular breathing, while criteria and available software for visual evaluation of TFV loops are lacking. We aimed to determine the reliability of standardised criteria for manual selection of infant TFV loops. Methods: Using a pre-defined set of criteria, three independent raters manually evaluated TFV loops among 57 randomly selected awake healthy 3-month-old infants with available TFV measurements in the Scandinavian Preventing Atopic Dermatitis and ALLergies in children (PreventADALL) study. The TFV loops were sampled using the Eco Medics Exhalyzer D. Criteria for selecting TFV loops included reproducible shape and volume with only one peak in tidal expiratory flow (PTEF), excluding loops with no clear or uneven flow towards PTEF. By intraclass coefficient (ICC), the reliability of agreement between raters was determined for the time to PTEF (t PTEF) to expiratory time (t E) and other TFV loop parameters. Results: Five infants had unsuccessful tests. Among the remaining 52 infants, the raters selected a median of 25, 26 and 15 loops per test. The ICCs (95% CI) were 0.97 (0.92-0.98) for t PTEF/t E, 0.99 (0.99-1.00) for respiratory rate, 0.98 (0.97-0.99) for tidal volume per kg and 0.98 (0.97-0.99) for expiratory volume, reflecting excellent agreement in all categories. Conclusion: Manual TFV loop selection using standardised criteria provides a reliable alternative for lung function measures in awake infants with interrupted breathing cycles in a real-life setting.

Skin Barrier Function and Infant Tidal Flow-Volume Loops-A Population-Based Observational Study.

Background: The relationship between the skin barrier- and lung function in infancy is largely unexplored. We aimed to explore if reduced skin barrier function by high transepidermal water loss (TEWL), or manifestations of eczema or Filaggrin (FLG) mutations, were associated with lower lung function in three-month-old infants. Methods: From the population-based PreventADALL cohort, 899 infants with lung function measurements and information on either TEWL, eczema at three months of age and/or FLG mutations were included. Lower lung function by tidal flow-volume loops was defined as a ratio of time to peak tidal expiratory flow to expiratory time (tPTEF/tE) <0.25 and a tPTEF <0.17 s (<25th percentile). A high TEWL >8.83 g/m2/h (>75th percentile) denoted reduced skin barrier function, and DNA was genotyped for FLG mutations (R501X, 2282del4 and R2447X). Results: Neither a high TEWL, nor eczema or FLG mutations, were associated with a lower tPTEF/tE. While a high TEWL was associated with a lower tPTEF; adjusted OR (95% CI) 1.61 (1.08, 2.42), the presence of eczema or FLG mutations were not. Conclusions: Overall, a high TEWL, eczema or FLG mutations were not associated with lower lung function in healthy three-month-old infants. However, an inverse association between high TEWL and tPTEF was observed, indicating a possible link between the skin barrier- and lung function in early infancy.

Maternal human papillomavirus infections at mid-pregnancy and delivery in a Scandinavian mother-child cohort study.

OBJECTIVES: Human papillomavirus (HPV) infections are common, especially during women's reproductive years, with unclear obstetrical impact. This study aimed to identify HPV prevalence at mid-gestation and delivery, type-specific persistence from mid-gestation to delivery, and risk factors for HPV infection and persistence. METHODS: In 757 women from a Scandinavian prospective mother-child cohort, HPV was analyzed in first-void urine samples at mid-gestation and delivery. We used Seegene Anyplex II HPV28 PCR assay for genotyping and semi-quantifying 28 genital HPV genotypes, including 12 high-risk HPVs (HR-HPV). Socio-demographic and health data were collected through e-questionnaires. RESULTS: Any-HPV genotype (any of 28 assessed) was detected in 38% of the study cohort at mid-gestation and 28% at delivery, and HR-HPVs in 24% and 16%, respectively. The most prevalent genotype was HPV16: 6% at mid-gestation and 4% at delivery. Persistence of Any-HPV genotype was 52%, as was HR-HPV genotype-specific persistence. A short pre-conception relationship with the child's father and alcohol intake during pregnancy increased HPV infection risk at both time points. Low viral load at mid-gestation was associated with clearance of HPV infections at delivery. CONCLUSION: HPV prevalence was higher at mid-gestation compared with delivery, and low viral load was associated with clearance of HPV at delivery.

Extract and molecular-based early infant sensitization and associated factors-A PreventADALL study.

BACKGROUND: More knowledge about sensitization patterns in early infancy, including impact of molecular allergology, is needed to help predict future allergy development more accurately. OBJECTIVE: We aimed to determine the prevalence and patterns of allergic sensitization at 3 months of age, and explore possible associated factors. METHODS: From the Scandinavian antenatally recruited PreventADALL mother-child cohort, we included 1110 3-month infants with available serum. Sensitization was defined as s-IgE of ≥0.1 kUA /L by Phadiatop Infant® (ThermoFisher Scientific) including birch, cat, grass, dog, milk, egg, peanut and wheat. Further ImmunoCAP analyses to ovomucoid, casein, Ara h 1-3, omega-5-gliadin were performed in food extract s-IgE-positive children. Maternal sensitization was defined as s-IgE ≥ 0.35 kUA /L to Phadiatop® (inhalant allergen mix) and/or Fx5 (food allergen mix) at 18-week pregnancy. RESULTS: Overall 79 (7.3%) infants had specific sensitization, many with low s-IgE-levels (IQR 0.16-0.81 kUA /L), with 78 being sensitized to food extract allergens; 41 to egg, 27 to milk, 10 to peanut, and 25 to wheat. A total of 62/78 were further analysed, 18 (29%) had s-IgE to ovomucoid, casein, Ara h 1-3 and/or omega-5-gliadin. Eight infants (0.7%) were sensitized to inhalant allergens. Maternal sensitization to food allergens was associated with infant sensitization, odds ratio 3.64 (95% CI 1.53-8.68). CONCLUSION: Already at 3 months of age, 7% were sensitized to food, mostly without detectable s-IgE to food allergen molecules, and <1% to inhalant allergens. Maternal food sensitization was associated with infants' sensitization.