Breastfeeding duration is inversely associated with asthma in Japanese children aged 3 years

Objective: Recent meta-analyses found an inverse relationship between breastfeeding duration and asthma in children. The present cross-sectional study investigated the associations between breastfeeding duration and the prevalence of wheeze and asthma in Japanese children aged 3 years. Methods: Subjects were 6412 children who participated in the Kyushu Okinawa Child Health Study. Data were collected using a self-administered questionnaire. Wheeze was defined according to the criteria of the International Study of Asthma and Allergies in Childhood. Asthma was considered present if the child had been diagnosed by a physician as having asthma. Associations of breastfeeding duration with wheeze and asthma were estimated using multivariate generalized estimating equation methods adjusted for maternal, family, and health characteristics. Results: The prevalence values of wheeze and asthma were 19.5% and 7.0%, respectively. Compared with <4 months of exclusive breastfeeding, exclusive breastfeeding for ≥4 months was not significantly associated with wheeze or asthma. Compared with <10 months of breastfeeding duration regardless of exclusivity, 10 to <14 months, 14 to <19 months, and 19 months or more of breastfeeding duration regardless of exclusivity were independently inversely related to asthma: the adjusted odds ratios [ORs; 95% confidence intervals (CIs)] were 0.69 (0.52–0.91, p = 0.01), 0.73 (0.56–0.97, p = 0.03), and 0.67 (0.51–0.88, p = 0.004), respectively. No association was found between breastfeeding duration regardless of exclusivity and wheeze. Conclusions: We confirmed an inverse association between breastfeeding duration regardless of exclusivity and asthma.     

Breastfeeding and timing of first dietary introduction in relation to childhood asthma,allergies, and airway diseases: A cross-sectional study

Objectives: We investigated associations of breastfeeding (BF) durations and patterns and of timing of other dietary introductions with prevalence of asthma, wheeze, hay fever, rhinitis, pneumonia, and eczema among preschool children. Methods: During April 2011-April 2012, we conducted a cross-sectional study in 72 kindergartens from five districts of Shanghai, China and obtained 13,335 questionnaires of children 4–6-years-old. We used multiple logistic regression models to evaluate the target associations. Results: Compared to children who were never BF, children who were exclusively breastfed 3–6 months had the lowest risk of asthma (adjusted odds ratio and 95% confidence interval: 0.81, 0.72–0.91) and wheeze (0.93, 0.87–0.99); and exclusive BF >6 months was significantly associated with a reduced risk of hay fever (0.93, 0.89–0.97), rhinitis (0.97, 0.94–0.99), pneumonia (0.97, 0.94–0.99), and eczema (0.96, 0.93–0.99). No significant associations were found between time when fruits or vegetables were introduced and the studied diseases. Associations were independent of the child's sex and parent's ownership of the current residence. Longer duration BF was only significantly protective when there was no family history of atopy. Conclusions: This study suggests that heredity, but not sex and socioeconomic status, may negatively impact the effect of BF on childhood airway and allergic diseases. Our findings support China's national recommendation that mothers provide exclusive BF for the first four months, and continue partial BF for more than 6 months.     

Does longer duration of breastfeeding prevent childhood asthma in low-income families?

Objective: The objective of this study was to examine the relationship of breastfeeding duration with childhood asthma among low-income families in Karachi, Pakistan. Methods: Mothers/caregivers of 200 children with asthma and an equal number of children without asthma were interviewed about breastfeeding duration. Based on the responses, 6 different binary variables were constructed: breastfeeding 3 months or less, 6 months or less, 9 months or less, 12 months or less, 18 months or less, and 24 months or less. Asthma status of the child was determined by clinical examination by a primary care physician. Data was analyzed using multiple logistic regression method, adjusted for age and sex of the child, household income, parental ethnicity, number of older siblings, family history of asthma or hay fever, presence of mold, parental smoking, number of people in the household, and body mass index of the child. Results: The average duration of breastfeeding was 21.4 months (SD = 7.33 months). Breastfeeding for at least 24 months was associated with increased odds of asthma (aOR = 1.77, 95%CI: 0.99, 3.16). Whereas breastfeeding for 12 months or less, and to some extent 18 months or less, was protective against childhood asthma. There was some evidence this protective effect may be delayed in children with a family history of asthma or hay fever. Conclusions: This study found breastfeeding for 12 months or less may have a protective effect against asthma. The protective effect weans down after 18 months, and if continued 24 months or more may place the child at-risk of asthma.     

Increased identification of the primary care provider as the main source of asthma care among urban minority children

Objective: Urban, minority, and disadvantaged youth with asthma frequently use emergency departments (EDs) for episodic asthma care instead of their primary care providers (PCPs). We sought to increase the rate of guardians' identification of the PCP as the source of asthma care for their children through integrated electronic health records and care coordination. Methods: In this prospective cohort study, we implemented an electronic communication process between an asthma specialty clinic and PCPs coupled with short-term care coordination in sample of youth aged 2–12 years with asthma and surveyed their guardians at baseline and 3 and 6 months after the intervention. Results: Guardians of 50 children (median age 5.8 years, 64% male, 98% African American, 94% public insurance) were enrolled. Compared to baseline, at 3 and 6 months after the intervention, significantly more guardians reported that the PCP was their child's primary asthma health care provider [70% at baseline, 85% at 3 months, 83% at 6 months (time averaged adjusted OR 77.4, 95% CI 3.0, 2027.1]. Further, significantly more guardians reported that they took their child to the PCP when the child experienced problems with his/her asthma [16% at baseline, 35% at 3 months, 41% at 6 months (time averaged adjusted odds ratio (OR) 10.6, 95% CI 2.7, 41.7]. Conclusion: Care in a subspecialty asthma clinic augmented by electronic communication with PCPs and short term care coordination was associated with significantly improved identification of PCPs as the primary source of asthma care in a cohort of urban minority youth.     

Frequent Ear Infections in Infancy and the Risk of Asthma in Mexican American Children

Objectives. This study examined the associations of history of ear infections in infancy with doctor-diagnosed asthma in a large sample of Mexican American children. Methods. In this population-based cross-sectional study, parents of 2023 children completed a questionnaire that collected data on doctor-diagnosed asthma, doctor-diagnosed ear infections, as well as antibiotics use in infancy, and other potential confounding variables. Results. Children with a history of ear infections in infancy were more likely to have asthma compared with those who had no history of ear infections in infancy; the adjusted odds ratios (ORs) were 2.52 (95% confidence interval [CI]: 1.35–4.69) and 1.27 (95% CI: 0.79–2.04) in children who had ≥3 and 1–2 (versus none) ear infections in infancy, respectively, p for trend = .0074. These associations were independent of antibiotics use, acetaminophen consumption, and history of various infections (other than ear infections) in the first year of life. In stratified analyses, the increased risk of asthma in children with recurrent ear infections in infancy persisted among children whose parents reported no lifetime history of rhinitis but not in children who had a history of rhinitis. Conclusions. This study demonstrated significant associations of asthma with history of ear infections in infancy, with a significant dose-response effect of repeated ear infections on the odds of asthma. These findings add to the growing body of literature linking early childhood infections with the risk of asthma and highlight the need for more research to identify the mechanisms through which ear infections may be associated with asthma.     

Effects of traffic-related air pollution on susceptibility to infantile bronchiolitis and childhood asthma: A cohort study in Korea

Objective: This study examined the role of exposure to traffic-related air pollution (TRAP) on susceptibility to asthma in children with past episodes of bronchiolitis. Methods: The baseline data included 2,627 school children aged 6–14 years who had participated in the longitudinal follow-up survey of the Children's Health and Environmental Research of Korea. Lifetime wheezing, past episodes of bronchiolitis, and doctor-diagnosed asthma were evaluated using an International Study of Asthma and Allergies in Childhood questionnaire. We used generalized linear regression with binomial distribution to calculate the relative risk (RR) between TRAP, assessed by proximity to a main road and the total length of roads, and asthma. Results: Compared with the subjects who had less than 100 m of road length within 200-m radius from their home, those with more than 500 m of road length had significantly increased odds for infantile bronchiolitis (adjusted OR [aOR]: 1.57, 95% confidence interval [CI]: 1.01–2.42). Positive exposure-response relationships were found between residential proximity to the main road and asthma (aOR: 1.79, 95% CI: 1.05–3.06; <75 m vs. >700 m from a main road, P for the trend = 0.02). Closer residential proximity to the main road (<75 m) and bronchiolitis combined increased the risks of newly diagnosed asthma (adjusted RR: 3.62, 95% CI: 1.07–12.26) compared with those without bronchiolitis and living ≥ 75 m away from the main road. Conclusions: TRAP appeared to be associated with an increased asthma among children with bronchiolitis, indicating the importance of modifying effects of bronchiolitis in asthma pathogenesis.     

The effect of early child care attendance on childhood asthma and wheezing: A meta-analysis

Objective: Research evidence offers mixed results regarding the relationship between early child care attendance and childhood asthma and wheezing. A meta-analysis was conducted to synthesize the current research evidence of the association between early child care attendance and the risk of childhood asthma and wheezing. Method: Peer reviewed studies published from 1964–January 2017 were identified in MEDLINE, CINAL, and EMBASE using MeSH headings relevant to child care and asthma. Two investigators independently reviewed the selected articles from this search. All relevant articles that met our inclusion criteria were selected for further analysis. Data were extracted from studies that had sufficient data to analyze the odds of asthma or wheezing among children who attended child care. Results: The meta-analysis of 32 studies found that (1) early child care attendance is protective against asthma in children 3–5 years of age but not for children with asthma 6 years of age or older. (2) Early child care attendance increases the risk of wheezing among children 2 years of age or younger, but not the risk of wheezing for children over 2 years of age. Conclusions: This meta-analysis shows that early child care attendance is not significantly associated with the risk of asthma or wheeze in children 6 years of age or older.     

A missed primary care appointment correlates with a subsequent emergency department visit among children with asthma

Objective: Since the Affordable Care Act's implementation, emergency department (ED) visits have increased. Poor asthma control increases the risk of acute exacerbations and preventable ED visits. The Centers for Medicare and Medicaid Services support the reduction of preventable ED visits to reduce healthcare spending. Implementation of interventions to avoid preventable ED visits has become a priority for many healthcare systems yet little data exist examining children's missed asthma management primary care (PC) appointments and subsequent ED visits. Methods: Longitudinal, retrospective review at a children's hospital was conducted for children with diagnosed asthma (ICD-9 493.xx), ages 2–18 years, scheduled for a PC visit between January 1, 2010, and June 30, 2012 (N = 3895). Records were cross-referenced with all asthma-related ED visits from January 1, 2010 to December 31, 2012. Logistic regression with maximum likelihood estimation was conducted. Results: None of the children who completed a PC appointment experienced an ED visit in the subsequent 6 months whereas 2.7% of those with missed PC appointments had an ED visit (χ² = 64.28, p <.0001). Males were significantly more likely to have an ED visit following a missed PC appointment than females (χ² = 34.37, p <.0001). There was a statistically significant interaction of sex × age. Younger children (<12 years) made more visits than older children. Conclusions: The importance of adherence to PC appointments for children with asthma as one mechanism for preventing ED visits was demonstrated. Interventions targeting missed visits could decrease asthma-related morbidity, preventable ED visits, and healthcare costs.     

National estimates of 30-day readmissions among children hospitalized for asthma in the United States

Objective: Previous single-center studies have reported that up to 40% of children hospitalized for asthma will be readmitted. The study objectives are to investigate the prevalence and timing of 30-day readmissions in children hospitalized with asthma, and to identify factors associated with 30-day readmissions. Methods: Data (n = 12,842) for children aged 6–18 years hospitalized for asthma were obtained from the 2013 Nationwide Readmission Database (NRD). The primary study outcome was time to readmission within 30 days after discharge attributable to any cause. Several predictors associated with the risk of admission were included: patient (age, sex, median household income, insurance type, county location, and pediatric chronic complex condition), admission (type, day, emergency services utilization, length of stay (LOS), and discharge disposition), and hospital (ownership, bed size, and teaching status). Cox's proportional hazards model was used to identify predictors. Results: Of 12,842 asthma-related index hospitalizations, 2.5% were readmitted within 30-days post-discharge. Time to event models identified significantly higher risk of readmission among asthmatic children aged 12–18 years, those who resided in micropolitan counties, those with >4-days LOS during index hospitalization, those who were hospitalized in an urban hospital, who had unfavorable discharge (hazard ratio 2.53, 95% confidence interval 1.33–4.79), and those who were diagnosed with a pediatric complex chronic condition, respectively, than children in respective referent categories. Conclusion: A multi-dimensional approach including effective asthma discharge action plans and follow-up processes, home-based asthma education, and neighborhood/community-level efforts to address disparities should be integrated into the routine clinical care of asthma children.     

Factors predicting future ACS episodes in children with sickle cell anemia

While a doctor‐diagnosis of asthma is associated with an increased risk of pain and acute chest syndrome (ACS) in children with sickle cell anemia (SCA), little is known about the relationship between specific asthma characteristics and clinical factors and future morbidity in children with SCA. We evaluated the relationship between (i) asthma risk factors at the time of a clinical visit (respiratory symptoms, maternal history of asthma, allergy skin tests, spirometry results) and (ii) the known risk factor of ACS early in life, on prospective pain and ACS episodes in a cohort of 159 children with SCA followed from birth to a median of 14.7 years. An ACS episode prior to 4 years of age, (incidence rate ratio [IRR] = 2.84; P < 0.001], female gender (IRR = 1.80; P = 0.009), and wheezing causing shortness of breath (IRR = 1.68; P = 0.042) were associated with future ACS rates. We subsequently added spirometry results (obstruction defined as FEV₁/FVC less than the lower limits of normal; and bronchodilator response, FEV₁ ≥ 12%) and prick skin test responses to the model. Only ≥ 2 positive skin tests had a significant effect (IRR 1.87; P = 0.01). Thus, early in life ACS events, wheezing causing shortness of breath, and ≥ 2 positive skin tests predict future ACS events. Am. J. Hematol. 89:E212–E217, 2014. © 2014 Wiley Periodicals, Inc.     

Disparities in emergency department visits in American children with asthma: 2006–2010

Objective: This article was to examine the trends in emergency department (ED) visits for asthma among American children in 2006–2010 across sociodemographic factors, parental smoking status, and children's body weight status. Methods: We analyzed 5,535 children aged 2–17 years with current asthma in the Asthma Call-Back Survey in 2006–2010. Multivariate log binomial regression was used to examine the disparities of ED visits by demographics, socioeconomic status, parental smoking status, children's body weight status, and the level of asthma control. We controlled for average state-level air pollutants. Prevalence ratios (PRs) and 95% confidence intervals (CIs) were reported. Results: Minority children with current asthma had higher risks of ED visits compared with white children in 2009 and 2010, e.g., the PR (95% CI) for black children in 2009 was 3.64 (1.79, 7.41). Children who had current asthma and more highly educated parents experienced a higher risk of ED visits in 2007 (PRs [95% CI] = 2.15 [1.02, 4.53] and 2.97 [1.29, 6.83] for children with some college or college-graduated parents), but not significant in other years. Children with uncontrolled asthma were significantly more likely to visit the ED in 2008 (PRs [95% CI] = 2.79 [1.44, 5.41] and 6.96 [3.55, 13.64] for not-well-controlled and very poorly controlled children with asthma). Conclusions: Minority children with current asthma or children with uncontrolled asthma were more likely to visit EDs for asthma treatment. However, the disparities in ED visits across sociodemographics, health status, or asthma control vary in scale and significance across time. More research is needed to explain these differences.     

The effects of respiratory infections, atopy, and breastfeeding on childhood asthma.

The objectives of the present study were to quantify the association of atopy and respiratory infections with asthma, and exclusive breastfeeding with respiratory illness, atopy and asthma in children. A cohort study of 2,602 children enrolled prior to birth and followed prospectively, provided data on respiratory illness, the method of feeding in the first year of life, as reported on a prospective diary card, and current asthma at the age of 6 yrs (defined as doctor-diagnosed asthma with wheeze in the last year or cough without a cold, and currently taking either preventer or reliever asthma medication), as reported by parental questionnaire. Atopy was defined by a positive skin-prick test assessed at the age of 6 yrs. Wheezing lower respiratory illness (LRI) in the first year of life, particularly multiple episodes of wheezing LRI, increased the risk for current asthma in both nonatopic (odds ratio (OR) 4.10, p< or =0.0005) and atopic children (OR 9.00, p< or =0.0005), but did not increase the risk for atopy. In contrast, up to three upper respiratory tract infections demonstrated a negative association and four or more a positive risk for current asthma in unadjusted (p=0.006) and adjusted (p=0.057) analysis. Following adjustment, exclusive breastfeeding for <4 months was associated with an increased risk for current asthma (OR 1.36, 95% confidence interval 1.00-1.85, p=0.047). Wheezing lower respiratory illness in the first year of life and atopy are independently associated with increased risk for current asthma at the age of 6 yrs, suggesting that their effects are mediated via different causal pathways and that these risk factors are multiplicative when they operate concomitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms.     

Evaluation of the PROMIS pediatric global health scale (PGH-7) in children with asthma

Objective: To evaluate the reliability and validity of the PROMIS Pediatric Global Health scale, a 7-item measure of perceived physical, mental, and social health, in children with asthma. Methods: From February 2014 to February 2015, convenience samples of 8–17 year-old children (n = 182) and parents of 5–17 year-old children (n = 328) visiting an emergency department for treatment of asthma were enrolled. The Asthma Control Test was used to characterize children as controlled versus not controlled, and the PROMIS Asthma Impact Scale was used to assess asthma symptoms' impact on functional status. We conducted longitudinal analyses among 92 children and 218 parents at 3 weeks, and 74 children and 171 parents at 8 weeks after enrollment. Results: The PGH-7 reliability ranged from 0.66 to 0.81 for child-report and 0.76 to 0.82 for parent-proxy. In cross-sectional analyses, children with controlled asthma had PGH-7 scores 0.40–0.95 standard deviation units higher than those who were uncontrolled. The PGH-7 was responsive to changes in overall general health between time points, with moderate effect sizes (0.5–0.6 standard deviation units). In longitudinal analyses, PGH-7 scores were no different between those who stayed uncontrolled versus became controlled at 3 weeks of follow-up; however, by 8 weeks of follow-up, the differences between these groups were 0.7–0.8 standard deviation units, indicative of large effects. Conclusions: The PGH-7 is a reliable and valid patient-reported outcome for assessing general health among children with asthma. It is a useful complement to other asthma-specific outcome measures.     

A Review of the Effects of Breastfeeding on Respiratory Infections, Atopy, and Childhood Asthma

The etiology of childhood asthma is not fully understood. Early exposure to certain respiratory infections may be protective for atopy and/or asthma whereas some infections have been suggested to exert the opposite effects. Wheezing lower respiratory illness (LRI) in the first year of life and atopy are independently associated with increased risk for current asthma in childhood and their effects are mediated via different causal pathways. These risk factors are multiplicative when they operate concommitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms. Furthermore, exclusive breastfeeding may protect against asthma and may reduce the incidence of lower respiratory illness, especially respiratory syncytial virus (RSV). We have previously demonstrated a protective effect of exclusive breastfeeding on asthmatic traits in children. The aim of this review was to clarify this protective association from intermediate associations with respiratory infections, atopy, or through other facets of breastfeeding. The bioactivity of breast milk and subsequent pathways that may act upon the development of asthma in children are explored.     

Individual factors,neighborhood social context and asthma at age 5 years

Objective: Childhood asthma is a major public health problem and its development is multifactorial. We examined whether neighborhood cohesion and disorder were associated with caregiver-report of asthma at age 5 years. Methods: This study is a secondary data analysis of the 2011–2012 United States National Survey of Children's Health. Data were available for 4680 children, age 5 years old born at term or preterm with birthweight >2500 g. Neighborhood disorder and cohesion were assessed based on caregivers' responses to validated questionnaires. Child asthma diagnosis was reported by the caregiver. Multivariable logistic regression was used to examine the relationship between these neighborhood factors and caregiver-report of child asthma, while accounting for individual level covariates. Results: Approximately two-thirds of the 4680 children were White and lived in households with income >400% of federal poverty line. Asthma was present in 399 (9%) children. Child female sex was associated with reduced risk of caregiver-reported asthma while non-Hispanic Black race and having smokers in the household were independently associated with increased risk in multivariable models. In these models, neighborhood disorder was significantly associated with asthma (adjusted Odds Ratio [aOR] 1.70, 95% Confidence Interval [CI] 1.04–2.78), while neighborhood cohesion was not (aOR 0.93, 95% CI 0.51–1.68). Conclusion: Even after adjustment for several individual level factors, neighborhood disorder was associated with caregiver-report of asthma in this nationally representative sample of 5-year-old children. Further research is needed to better understand how risk factors at different levels of the socio-ecological framework may interact to affect childhood asthma development.     

A review of the effects of breastfeeding on respiratory infections, atopy, and childhood asthma.

The etiology of childhood asthma is not fully understood. Early exposure to certain respiratory infections may be protective for atopy and/or asthma whereas some infections have been suggested to exert the opposite effects. Wheezing lower respiratory illness (LRI) in the first year of life and atopy are independently associated with increased risk for current asthma in childhood and their effects are mediated via different causal pathways. These risk factors are multiplicative when they operate concommitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms. Furthermore, exclusive breastfeeding may protect against asthma and may reduce the incidence of lower respiratory illness, especially respiratory syncytial virus (RSV). We have previously demonstrated a protective effect of exclusive breastfeeding on asthmatic traits in children. The aim of this review was to clarify this protective association from intermediate associations with respiratory infections, atopy, or through other facets of breastfeeding. The bioactivity of breast milk and subsequent pathways that may act upon the development of asthma in children are explored.     

Bedeutung des Stillens für diabetische Mütter und ihre Kinder

Background

Exclusive breastfeeding provides optimal nutrition and health protection for mothers and their offspring.

Health benefits of breastfeeding for diabetic women

Diabetic mothers who breastfeed in the first 4 months postpartum have improved metabolic parameters, e.g., lower blood lipids, lower blood glucose, and greater insulin sensitivity. Studies have reported that longer duration of breastfeeding in women with a history of gestational diabetes may reduce long-term risks of cardiometabolic disease, including type 2 diabetes.

Health benefits of breastfeeding for children

Children of diabetic mothers may benefit from breastfeeding in that they have lower rates of hypoglycemia immediately after birth and lower rates of obesity in later life. It has been suggested that the latter benefits may only be observed if breastfeeding is continued beyond a certain period where breastmilk composition would have normalized over time.

Conclusion

Due to several risk factors and pathophysiological mechanisms, diabetic women are less likely and for a shorter duration to breastfeed. Therefore, diabetic women should be encouraged to breastfeed exclusively for at least 4–6 months to improve maternal and child morbidity, to prevent noncommunicable diseases in later life, and to decrease health care costs.

     

Pediatric asthma hospitalizations among urban minority children and the continuity of primary care

Objective: To examine the effect of ambulatory health care processes on asthma hospitalizations. Methods: A retrospective cohort study using electronic health records was completed. Patients aged 2–18 years receiving health care from 1 of 5 urban practices between Jan 1, 2004 and Dec 31, 2008 with asthma documented on their problem list were included. Independent variables were modifiable health care processes in the primary care setting: (1) use of asthma controller medications; (2) regular assessment of asthma symptoms; (3) use of spirometry; (4) provision of individualized asthma care plans; (5) timely influenza vaccination; (6) access to primary healthcare; and (7) use of pay for performance physician incentives. Occurrence of one or more asthma hospitalizations was the primary outcome of interest. We used a log linear model (Poisson regression) to model the association between the factors of interest and number of asthma hospitalizations. Results: 5,712 children with asthma were available for analysis. 96% of the children were African American. The overall hospitalization rate was 64 per 1,000 children per year. None of the commonly used asthma-specific indicators of high quality care were associated with fewer asthma hospitalizations. Children with documented asthma who experienced a lack of primary health care (no more than one outpatient visit at their primary care location in the 2 years preceding hospitalization) were at higher risk of hospitalization compared to those children with a greater number of visits (incidence rate ratio 1.39; 95% CI 1.09–1.78). Conclusions: In children with asthma, more frequent primary care visits are associated with reduced asthma hospitalizations.     

Association of living in a farming environment with asthma incidence in Canadian children

Objective: The objective of this population-based 14-year follow-up study was to examine the effect of living in a farm environment on asthma incidence in children. Methods: A total of 10,941 children of ages 0 to 11 years who were free of asthma and wheeze at the baseline (1994–1995) in the National Longitudinal Survey of Children and Youth were considered in the study. Children's living environment was classified, based on interviewer's observation, into three categories: non-rural, rural non-farming, and farming. An incidence of asthma was obtained from health-professional diagnosed asthma reported either by the person most knowledgeable for children under 15 years or by the children themselves if they were of ages 16 years and over. Results: The 14-year cumulative incidence of asthma among children living in farming environments was 10.18%, which was significantly lower than that observed for children living in rural non-farming (13.12%) and non-rural environments (16.50%). After adjusting for age group, number of older siblings, allergy, parental history of asthma, dwelling in need of repairs and SES index, a dose-response relationship was observed with children living in rural non-farming and farming environments having significantly reduced risk of asthma [hazard ratio (HR): 0.77; 95% confidence interval (CI): (0.60, 1.00); p = 0.047 and HR: 0.56; 95% CI: (0.41,0.77); p < 0.001] in comparison to those living in non-rural environments. Conclusion: This cohort study provides further evidence that living in a farming environment during childhood is protective of asthma incidence in adolescence and adulthood and this finding provides further support for the hygiene hypothesis.