Epigenomic Profiling of Human CD4+ T Cells Supports a Linear Differentiation Model and Highlights Molecular Regulators of Memory Development.

The impact of epigenetics on the differentiation of memory T (Tmem) cells is poorly defined. We generated deep epigenomes comprising genome-wide profiles of DNA methylation, histone modifications, DNA accessibility, and coding and non-coding RNA expression in naive, central-, effector-, and terminally differentiated CD45RA+ CD4+ Tmem cells from blood and CD69+ Tmem cells from bone marrow (BM-Tmem). We observed a progressive and proliferation-associated global loss of DNA methylation in heterochromatic parts of the genome during Tmem cell differentiation. Furthermore, distinct gradually changing signatures in the epigenome and the transcriptome supported a linear model of memory development in circulating T cells, while tissue-resident BM-Tmem branched off with a unique epigenetic profile. Integrative analyses identified candidate master regulators of Tmem cell differentiation, including the transcription factor FOXP1. This study highlights the importance of epigenomic changes for Tmem cell biology and demonstrates the value of epigenetic data for the identification of lineage regulators.

The role of the 5' sensing function of ribonuclease E in cyanobacteria.

RNA degradation is critical for synchronising gene expression with changing conditions in prokaryotic and eukaryotic organisms. In bacteria, the preference of the central ribonucleases RNase E, RNase J and RNase Y for 5'-monophosphorylated RNAs is considered important for RNA degradation. For RNase E, the underlying mechanism is termed 5' sensing, contrasting to the alternative 'direct entry' mode, which is independent of monophosphorylated 5' ends. Cyanobacteria, such as Synechocystis sp. PCC 6803 (Synechocystis), encode RNase E and RNase J homologues. Here, we constructed a Synechocystis strain lacking the 5' sensing function of RNase E and mapped on a transcriptome-wide level 283 5'-sensing-dependent cleavage sites. These included so far unknown targets such as mRNAs encoding proteins related to energy metabolism and carbon fixation. The 5' sensing function of cyanobacterial RNase E is important for the maturation of rRNA and several tRNAs, including tRNAGluUUC. This tRNA activates glutamate for tetrapyrrole biosynthesis in plant chloroplasts and in most prokaryotes. Furthermore, we found that increased RNase activities lead to a higher copy number of the major Synechocystis plasmids pSYSA and pSYSM. These results provide a first step towards understanding the importance of the different target mechanisms of RNase E outside Escherichia coli.

Transcriptome-wide in vivo mapping of cleavage sites for the compact cyanobacterial ribonuclease E reveals insights into its function and substrate recognition.

Ribonucleases are crucial enzymes in RNA metabolism and post-transcriptional regulatory processes in bacteria. Cyanobacteria encode the two essential ribonucleases RNase E and RNase J. Cyanobacterial RNase E is shorter than homologues in other groups of bacteria and lacks both the chloroplast-specific N-terminal extension as well as the C-terminal domain typical for RNase E of enterobacteria. In order to investigate the function of RNase E in the model cyanobacterium Synechocystis sp. PCC 6803, we engineered a temperature-sensitive RNase E mutant by introducing two site-specific mutations, I65F and the spontaneously occurred V94A. This enabled us to perform RNA-seq after the transient inactivation of RNase E by a temperature shift (TIER-seq) and to map 1472 RNase-E-dependent cleavage sites. We inferred a dominating cleavage signature consisting of an adenine at the -3 and a uridine at the +2 position within a single-stranded segment of the RNA. The data identified mRNAs likely regulated jointly by RNase E and an sRNA and potential 3' end-derived sRNAs. Our findings substantiate the pivotal role of RNase E in post-transcriptional regulation and suggest the redundant or concerted action of RNase E and RNase J in cyanobacteria.

Biallelic variants in ZNF142 lead to a syndromic neurodevelopmental disorder.

Biallelic variants of the gene encoding for the zinc-finger protein 142 (ZNF142) have recently been associated with intellectual disability (ID), speech impairment, seizures, and movement disorders in nine individuals from five families. In this study, we obtained phenotype and genotype information of 26 further individuals from 16 families. Among the 27 different ZNF142 variants identified in the total of 35 individuals only four were missense. Missense variants may give a milder phenotype by changing the local structure of ZF motifs as suggested by protein modeling; but this correlation should be validated in larger cohorts and pathogenicity of the missense variants should be investigated with functional studies. Clinical features of the 35 individuals suggest that biallelic ZNF142 variants lead to a syndromic neurodevelopmental disorder with mild to moderate ID, varying degrees of delay in language and gross motor development, early onset seizures, hypotonia, behavioral features, movement disorders, and facial dysmorphism. The differences in symptom frequencies observed in the unpublished individuals compared to those of published, and recognition of previously underemphasized facial features are likely to be due to the small sizes of the previous cohorts, which underlines the importance of larger cohorts for the phenotype descriptions of rare genetic disorders.

Specific microbiota enhances intestinal IgA levels by inducing TGF-ß in T follicular helper cells of Peyer's patches in mice.

In humans and mice, mucosal immune responses are dominated by IgA antibodies and the cytokine TGF-ß, suppressing unwanted immune reactions but also targeting Ig class switching to IgA. It had been suggested that eosinophils promote the generation and maintenance of mucosal IgA-expressing plasma cells. Here, we demonstrate that not eosinophils, but specific bacteria determine mucosal IgA production. Co-housing of eosinophil-deficient mice with mice having high intestinal IgA levels, as well as the intentional microbiota transfer induces TGF-ß expression in intestinal T follicular helper cells, thereby promoting IgA class switching in Peyer's patches, enhancing IgA+ plasma cell numbers in the small intestinal lamina propria and levels of mucosal IgA. We show that bacteria highly enriched for the genus Anaeroplasma are sufficient to induce these changes and enhance IgA levels when adoptively transferred. Thus, specific members of the intestinal microbiota and not the microbiota as such regulate gut homeostasis, by promoting the expression of immune-regulatory TGF-ß and of mucosal IgA.

[Treatment of geriatric patients with end-stage renal failure : Dialysis or conservative procedure?] / Versorgung des geriatrischen Patienten mit terminaler Niereninsuffizienz : Dialyse oder eher konservatives Prozedere?

Compared to younger patients, an acceptable state of health in older patients with various comorbidities is rarely achieved by the initiation of dialysis. Despite dialysis treatment, further functional and cognitive impairments often rapidly occur in geriatric patients. Thus, newer studies are concerned with the quality of life of this patient group after initiation of dialysis as well as with palliative treatment strategies as alternatives. A structured clarification for the patients on all possibilities with mediation of all necessary information is a prerequisite for a shared decision-making. To assess life expectancy after dialysis initiation, various scores have been developed but the sensitivity could not fulfil the expectations. In the case of renal replacement, chronic intermittent hemodialysis is the treatment form most frequently performed in geriatric patients. The main concern of conservative palliative treatment is the quality of life and the management of uremic symptoms, which have to be addressed by a multidisciplinary team.

Impact of iron oxide nanoparticles on xenobiotic metabolism in HepaRG cells.

Iron oxide nanoparticles are used in various industrial fields, as a tool in biomedicine as well as in food colorants, and can therefore reach human metabolism via oral uptake or injection. However, their effects on the human body, especially the liver as one of the first target organs is still under elucidation. Here, we studied the influence of different representative iron oxide materials on xenobiotic metabolism of HepaRG cells. These included four iron oxide nanoparticles, one commercially available yellow food pigment (E172), and non-particulate ionic control FeSO4. The nanoparticles had different chemical and crystalline structures and differed in size and shape and were used at a concentration of 50 µg Fe/mL. We found that various CYP enzymes were downregulated by some but not all iron oxide nanoparticles, with the Fe3O4-particle, both γ-Fe2O3-particles, and FeSO4 exhibiting the strongest effects, the yellow food pigment E172 showing a minor effect and an α-Fe2O3 nanoparticle leading to almost no inhibition of phase I machinery. The downregulation was seen at the mRNA, protein expression, and activity levels. Thereby, no dependency on the size or chemical structure was found. This underlines the difficulty of the grouping of nanomaterials regarding their physiological impact, suggesting that every iron oxide nanoparticle species needs to be evaluated in a case-by-case approach.

The role of wrist monitors to measure blood pressure in older adults.

BACKGROUND: Arterial hypertension is a common condition in older adults with increasing data about blood pressure (BP) targets and antihypertensive treatment in this population. Recent studies have opened new discussions about the different usual and unusual methods of blood pressure monitoring. However, there are no evidence-based recommendations whether BP should be measured at upper arms or at wrist, which seems to be more comfortable in older and frail people. AIMS: The purpose of this study was to test the quality of wrist BP monitors as diagnostic method in older adults. METHODS: BP measurements at both upper arms and at both wrists were compared under standardized conditions in 605 patients ≥ 75 years. Differences in wrist and upper arm BP were, furthermore, correlated with various diagnoses and parameters including ankle-brachial-index (ABI). RESULTS: In patients of 75-80 years, there were no differences in BP measurements at upper arms compared to wrists whereas in patients > 80 years, BP measurements at wrists were significantly lower than at upper arms. In both age groups BP measured at wrist was significantly lower in patients with ABI < 0.9. CONCLUSIONS: BP wrist monitors could be considered as a serious alternative in adults of 75-80 years or in older persons with normal ABI values.

What does lung function tell us about respiratory multimorbidity in childhood and early adulthood? Results from the MAS birth cohort study.

BACKGROUND: Interaction between respiratory multimorbidity and lung function has not been examined in longitudinal population studies. We aimed to assess the association of multimorbidity of asthma and rhinitis with lung function and bronchial hyperresponsiveness in comparison with single and no allergies from early school age to young adulthood. METHODS: In 1990, the Multicenter Allergy Study birth cohort recruited 1314 newborns from 5 German cities. At 7, 13, and 20 years, we performed lung function and bronchial challenge tests. We assessed symptoms, medications, and doctor's diagnoses for asthma and rhinitis for 3 outcomes: current multimorbidity (both coexisting), asthma only, and rhinitis only. RESULTS: From 7 to 20 years, multimorbidity prevalence more than doubled from 3.5% to 7.7%, current asthma only (without rhinitis co-occurring) decreased by half from 2.8% to 1.3%, and current rhinitis only (without asthma co-occurring) increased from 14.3% to 41.6%. Resting lung function parameters differed between allergic and asymptomatic participants but showed no considerable differences between the allergic phenotypes. Frequency and severity of bronchial hyperresponsiveness were particularly associated with multimorbidity. At the age of 20 years, participants with multimorbidity showed a clearly higher severity in hyperresponsiveness compared to participants who suffered only asthma (P = .049) or rhinitis (P = .008) or were asymptomatic (P < .001). CONCLUSION: Single lung function measurements from childhood ongoing do not seem to discriminate between subjects with multimorbidity, single allergies, and no allergy. Our results show that multimorbidity is associated with more severe symptoms compared to those suffering only a single allergic disease.

IgG and IgG4 to 91 allergenic molecules in early childhood by route of exposure and current and future IgE sensitization: Results from the Multicentre Allergy Study birth cohort.

BACKGROUND: Studies of a limited number of allergens suggested that nonsensitized children produce IgG responses mainly to foodborne allergens, whereas IgE-sensitized children also produce strong IgG responses to the respective airborne molecules. OBJECTIVE: We sought to systematically test the hypothesis that both the route of exposure and IgE sensitization affect IgG responses to a broad array of allergenic molecules in early childhood. METHODS: We examined sera of 148 children participating in the Multicentre Allergy Study, a birth cohort born in 1990. IgG to 91 molecules of 42 sources were tested with the ImmunoCAP Solid-Phase Allergen Chip (ISAC; TFS, Uppsala, Sweden). IgE sensitization at age 2 and 7 years was defined by IgE levels of 0.35 kUA/L or greater to 1 or more of 8 or 9 extracts from common allergenic sources, respectively. RESULTS: The prevalence and geometric mean levels of IgG to allergenic molecules in nonsensitized children were lower at age 2 years than in IgE-sensitized children, and they were extremely heterogeneous: highest for animal food (87% ± 13%; 61 ISAC Standardized Units [ISU], [95% CI, 52.5-71.5 ISU]), intermediate for vegetable food (48% ± 27%; 13 ISU [95% CI, 11.2-16.1 ISU]), and lowest for airborne allergens (24% ± 20%; 3 ISU [95% CI, 2.4-3.4 ISU]; P for trend < .001 [for percentages], P for trend < .001 [for levels]). IgG4 antibodies were infrequent (<5%) and contributed poorly (<3%) to overall IgG antibody levels. IgG responses at age 2 years were slightly more frequent and stronger among children with than in those without IgE sensitization at age 7 years. CONCLUSION: The children's repertoire of IgG antibodies at 2 years of age to a broad array of animal foodborne, vegetable foodborne, and airborne allergenic molecules is profoundly dependent on the route of allergen exposure and the child's IgE sensitization status and only marginally involves the IgG4 isotype.

Multivalent Peptide-Nanoparticle Conjugates for Influenza-Virus Inhibition.

To inhibit binding of the influenza A virus to the host cell glycocalyx, we generate multivalent peptide-polymer nanoparticles binding with nanomolar affinity to the virus via its spike protein hemagglutinin. The chosen dendritic polyglycerol scaffolds are highly biocompatible and well suited for a multivalent presentation. We could demonstrate in vitro that by increasing the size of the polymer scaffold and adjusting the peptide density, viral infection is drastically reduced. Such a peptide-polymer conjugate qualified also in an in vivo infection scenario. With this study we introduce the first non-carbohydrate-based, covalently linked, multivalent virus inhibitor in the nano- to picomolar range by ensuring low peptide-ligand density on a larger dendritic scaffold.

miR-148a is upregulated by Twist1 and T-bet and promotes Th1-cell survival by regulating the proapoptotic gene Bim.

Repeatedly activated T helper 1 (Th1) cells present during chronic inflammation can efficiently adapt to the inflammatory milieu, for example, by expressing the transcription factor Twist1, which limits the immunopathology caused by Th1 cells. Here, we show that in repeatedly activated murine Th1 cells, Twist1 and T-bet induce expression of microRNA-148a (miR-148a). miR-148a regulates expression of the proapoptotic gene Bim, resulting in a decreased Bim/Bcl2 ratio. Inhibition of miR-148a by antagomirs in repeatedly activated Th1 cells increases the expression of Bim, leading to enhanced apoptosis. Knockdown of Bim expression by siRNA in miR-148a antagomir-treated cells restores viability of the Th1 cells, demonstrating that miR-148a controls survival by regulating Bim expression. Thus, Twist1 and T-bet not only control the differentiation and function of Th1 cells, but also their persistence in chronic inflammation.

Timed action of IL-27 protects from immunopathology while preserving defense in influenza.

Infection with influenza virus can result in massive pulmonary infiltration and potentially fatal immunopathology. Understanding the endogenous mechanisms that control immunopathology could provide a key to novel adjunct therapies for this disease. Here we show that the cytokine IL-27 plays a crucial role in protection from exaggerated inflammation during influenza virus infection. Using Il-27ra-/- mice, IL-27 was found to limit immunopathology, neutrophil accumulation, and dampened TH1 or TH17 responses via IL-10-dependent and -independent pathways. Accordingly, the absence of IL-27 signals resulted in a more severe disease course and in diminished survival without impacting viral loads. Consistent with the delayed expression of endogenous Il-27p28 during influenza, systemic treatment with recombinant IL-27 starting at the peak of virus load resulted in a major amelioration of lung pathology, strongly reduced leukocyte infiltration and improved survival without affecting viral clearance. In contrast, early application of IL-27 impaired virus clearance and worsened disease. These findings demonstrate the importance of IL-27 for the physiological control of immunopathology and the potential value of well-timed IL-27 application to treat life-threatening inflammation during lung infection.

Identification of Targeting Peptides for Mucosal Delivery in Sheep and Mice.

In this study we identified and characterized a novel cyclic peptide that facilitates the rapid transportation of conjugated molecules across the epithelial layer of the small intestine. The peptide was initially selected from phage display libraries using a large animal experimental model, which employed consecutive in vitro and in vivo panning. The procedure was designed to enrich for peptides that facilitated transcytosis across the intestinal epithelium into the intestinal afferent lymphatic system. A small set of peptides was repeatedly isolated using this selection method; however, the cyclic nonamer CTANSSAQC, 13C, dominated. The activity of the putative targeting peptide 13C was then verified using a mouse model. These experiments showed that the 13C peptide as well as macromolecules conjugated to it were rapidly transported across the intestinal mucosa into distinct subsets of epithelial cells and CD11c+ cells located in the lamina propria and Peyer's Patches. Significant amounts of intact protein could be delivered into the systemic circulation after rectal and nasal application. Thus, peptide 13C is regarded as an attractive carrier candidate for mucosal delivery of large molecules. The preferential targeting to distinct intestinal cells may be utilized to deliver active biological drugs for the effective control of diseases of the gut.

Prediction and prevention of allergic rhinitis: A birth cohort study of 20 years.

BACKGROUND: Allergic rhinitis (AR) is one of the most common chronic diseases, usually starting in the first 2 decades of life. Information on predictors, risk, and protective factors is missing because of a lack of long-term prospective studies. OBJECTIVE: Our aim was to examine early-life environmental and lifestyle determinants for AR up to age 20 years. METHODS: In 1990, the Multicenter Allergy Study included 1314 newborns in 5 German cities. Children were evaluated at 19 time points. A Cox regression model examined the associations between 41 independent early-life factors and onset of AR (as the primary outcome), including sensitization against aeroallergens and the secondary outcomes of nonallergic rhinitis and AR plus asthma. RESULTS: Two hundred ninety subjects had AR within 13,179 person years observed. The risk of AR was higher with a parental history of AR (adjusted hazard ratio [aHR], 2.49; 95% CI, 1.93-3.21), urticaria (aHR, 1.32; 95% CI, 1.00-1.74), or asthma (aHR, 1.29; 95% CI, 0.95-1.75). Early allergic sensitization (aHR, 4.53; 95% CI, 3.25-6.32), eczema within the first 3 years of life (aHR, 1.83; 95% CI, 1.38-2.42), male sex (aHR, 1.28; 95% CI, 1.02-1.61), and birthday in summer or autumn (aHR, 1.26; 95% CI, 1.00-1.58) were independent predictors of AR up to age 20 years. None of the other socioeconomic, environmental, lifestyle, pregnancy, and birth-related factors were associated with AR. CONCLUSION: Only nonmodifiable factors, particularly early allergic sensitization or eczema and parental AR, predicted AR up to age 20 years. No modifiable aspects of early-life environment or lifestyle were identified as targets for primary prevention.

Tolerogenic modulation of the immune response by oligoglycerol- and polyglycerol-peptide conjugates.

Peptide-based therapy is a promising strategy for antigen-specific immunosuppression to treat or even heal autoimmune diseases with significantly reduced adverse effects compared to conventional therapies. However, there has been no major success due to the drawbacks of native peptides, i.e., limited bioavailability. Considering the importance and limitations of peptide-based therapies for treatment of autoimmune diseases, we designed and constructed oligoglycerol (OG)- and polyglycerol (PG)-based peptide conjugates. They were evaluated for their biological activity (in vitro and in vivo), bioavailability, and tolerogenic potential. Among the OG- and PG-peptide constructs, PG-peptide constructs exhibited an extended bioavailability compared to OG-peptide constructs and unconjugated peptide. Interestingly, size, structure, and linker chemistry played a critical role for the tolerogenic capacity of the constructs. The PG-peptide construct bound via an ester linkage was the most tolerogenic conjugate, while the PG-peptide construct bound via an amide induced stronger proliferation, but also higher TNF production and lower frequencies of Foxp3(+) regulatory T-cells. Therefore, we conclude that PG-peptide conjugates bound via an ester linkage are not only promising candidates for tolerogenic vaccination, but also open a new avenue toward the application of peptides for the treatment of autoimmune diseases.

Allergic multimorbidity of asthma, rhinitis and eczema over 20 years in the German birth cohort MAS.

BACKGROUND: The occurrence of allergic multimorbidity (coexistence of asthma, allergic rhinitis and eczema) has not been evaluated longitudinally from early childhood up to adulthood in a population-based study sample. We aimed to determine the prevalence of allergic multimorbidity up to age 20 stratified by parental allergies and sex/gender using extensive prospective follow-up data from two decades of a birth cohort study. METHODS: In 1990, we recruited 1314 healthy newborns from 6 maternity wards across Germany for the population-based MAS birth cohort study. The sample was purposely risk-enriched by increasing the proportion of children at high allergy risk (i.e. at least 2 allergic family members among parents and siblings) from 19% in the source population to 38% in the final sample. The remaining 62% of all MAS children had a low or no allergy risk. Symptoms, medication and doctor's diagnoses of allergic diseases have been assessed using standardized questionnaires including validated ISAAC questions in 19 follow-up assessments up to age 20. Allergic multimorbidity at each time point was defined as the coexistence of at least 2 of the following diseases in one participant: asthma, allergic rhinitis and eczema. RESULTS: Response at age 20 was 72% (n = 942) of all recruited participants. At age 20, 18.5% (95% CI, 15.0-22.5%) of all participants with allergic parents had 2 or 3 concurrent allergies as compared to only 6.3% (95% CI, 4.3-9.0%) of those with non-allergic parents. At this age, allergic multimorbidity was similar in women and men (12.7% (95% CI, 9.7-16.2%) vs. 11.6% (95% CI, 8.9-14.8%)), whereas single allergic diseases were slightly more common in women than men (24.2% (95% CI, 20.2-28.5%) vs. 20.1% (95% CI, 16.6-24.0%)). Asthma occurred more frequently with coexisting allergic rhinitis and/or eczema than as a single entity from pre-puberty to adulthood. CONCLUSION: Having parents with allergies is not only a strong predictor to develop any allergy, but it strongly increases the risk of developing allergic multimorbidity. In males and females alike, coexisting allergies were increasingly common throughout adolescence up to adulthood. Particularly asthma occurred in both sexes more frequently with coexisting allergies than as a single entity.

The association between physical activity and healthcare costs in children--results from the GINIplus and LISAplus cohort studies.

BACKGROUND: Physical inactivity in children is an important risk factor for the development of various morbidities and mortality in adulthood, physical activity already has preventive effects during childhood. The objective of this study is to estimate the association between physical activity, healthcare utilization and costs in children. METHODS: Cross-sectional data of 3356 children aged 9 to 12 years were taken from the 10-year follow-up of the birth cohort studies GINIplus and LISAplus, including information on healthcare utilization and physical activity given by parents via self-administered questionnaires. Using a bottom-up approach, direct costs due to healthcare utilization and indirect costs resulting from parental work absence were estimated for the base year 2007. A two-step regression model compared effects on healthcare utilization and costs for a higher (≥ 7 h/week) versus a lower (<7 h/week) level of moderate-to-vigorous physical activity (MVPA) adjusted for age, gender, BMI, education and income of parents, single parenthood and study region. Recycled predictions estimated adjusted mean costs per child and activity group. RESULTS: The analyses for the association between physical activity, healthcare utilization and costs showed no statistically significant results. Different directions of estimates were noticeable throughout cost components in the first step as well as the second step of the regression model. For higher MVPA (≥ 7 h/week) compared with lower MVPA (< 7 h/week) total direct costs accounted for 392 EUR (95% CI: 342-449 EUR) versus 398 EUR (95% CI: 309-480 EUR) and indirect costs accounted for 138 EUR (95% CI: 124-153 EUR) versus 127 EUR (95% CI: 111-146 EUR). CONCLUSIONS: The results indicate that childhood might be too early in life, to detect significant preventive effects of physical activity on healthcare utilization and costs, as diseases attributable to lacking physical activity might first occur later in life. This underpins the importance of clarifying the long-term effects of physical activity as it may strengthen the promotion of physical activity in children from a health economic perspective.

Early-life determinants of asthma from birth to age 20 years: a German birth cohort study.

BACKGROUND: The lack of longitudinal data analyses from birth to adulthood is hampering long-term asthma prevention strategies. OBJECTIVE: We aimed to determine early-life predictors of asthma incidence up to age 20 years in a birth cohort study by applying time-to-event analysis. METHODS: In 1990, the Multicenter Allergy Study included 1314 newborns in 5 German cities. Children were evaluated from birth to age 20 years at 19 time points. Using a Cox regression model, we examined the associations between 36 early-life factors and onset of asthma based on a doctor's diagnosis or asthma medication (primary outcome), typical asthma symptoms, or allergic asthma (including positive IgE measurements). RESULTS: Response at 20 years was 71.6%. Two hundred eighteen subjects met the primary outcome criteria within 16,257 person years observed. Asthma incidence was lower in participants who were vaccinated (measles, mumps, and rubella vaccine/tick-borne encephalitis vaccine/BCG vaccine: adjusted hazard ratio [HR], 0.66 [95% CI, 0.47-0.93]). Up to age 20 years, asthma incidence was higher in subjects who had parents with allergic rhinitis (adjusted HR, 2.24 [95% CI, 1.67-3.02]), started day care early or late (before 18 months: adjusted HR, 1.79 [95% CI, 1.03-3.10]; after 3 years: adjusted HR, 1.64 [95% CI, 0.96-2.79]), had mothers who smoked during pregnancy (adjusted HR, 1.79 [95% CI, 1.20-2.67]), had poor parents (adjusted HR, 1.55 [95% CI, 1.09-2.22]), and had parents with asthma (adjusted HR, 1.65 [95% CI, 1.17-2.31]). Not associated with asthma were aspects of diet and breast-feeding, pet ownership, presence of older siblings, and passive smoking. CONCLUSION: Parental asthma and nasal allergy increase asthma incidence in offspring up to adulthood. Avoiding tobacco smoke exposure during pregnancy, receiving vaccinations in early childhood, and starting day care between 1.5 and 3 years of age might prevent or delay the development of asthma.