Usual dietary salt intake and asthma in children: a case-control study.

Abstract

Background -A decline in host resistance due to an alteration in diet -primarily of salt -was recently put forward as a possible explanation for rising rates of asthma. Methods -A case-control study was coducted in participants in a prevalence survey which included 187 children with asthma (defined by prior diagnosis and/or a decline in forced expiratory volume in one second (FEVy) of > 10% after exercise) and 145 age and sex matched controls. Subjects were selected from 989 children aged 5-13 years attending 18 elementary schools on the island of Montreal. Usual dietary salt intake was estimated from a food frequency questionnaire administered to the mother, and a salt intake score was used to group the children into quartiles from I (lowest) to IV (highest salt intake). Bronchial hyperresponsiveness to methacholine was assessed by Yan's method. Cases and controls were combined in one group to examine the relationship of salt intake to bronchial hyperresponsiveness to methacholine. Methacholine responsiveness was expressed as a dose-response slope and ranks of dose-response slopes were used in the analysis. Results -After accounting for important confounding variables, there was no association between asthma and salt intake, while methacholine dose-response slope ranks increased with increasing salt intake and methacholine responsiveness was greater in the highest quartile than in the lowest quartile of salt intake. The median dose-response slopes in % fall in FEVy per 1tmol methacholine for quartiles I, II, III, and IV were 5 4, 5.9, 7.7, and 8-7.Conclusions -No association was found between asthma or exercise-induced bronchospasm and dietary salt intake. Bronchial hyperresponsiveness to methacholine did, however, appear to increase with greater salt intake, but the relevance of this association to asthma is unclear.

Diet and childhood asthma in a society in transition: a study in urban and rural Saudi Arabia

“…The role of salt in this study merits some comment, since our findings contrast with earlier suggestions that a high salt intake increases the risk of asthma (although a more recent study has not confirmed this32). Our study was carried out in a country where the temperature requires a high salt intake for health, and it may be that a low intake is simply a marker for an otherwise poor diet in these circumstances.…”

Diet, interleukin-17, and childhood asthma in Puerto Ricans

“…Daily consumption of soda or soft drinks has been associated with increased risk of asthma among high school students in the U.S.(32) and Australian adults(33). Intake of soft drinks and salty snacks may lead to asthma through sensitivity to food preservatives such as sulfites(34) or increased sodium content (which has been linked to airway hyper-responsiveness [AHR] in children with asthma)(35). A recent study indicates that non-caloric artificial sweeteners alter microbial metabolic pathways linked to host susceptibility to dysbiosis and glucose intolerance(36); dysregulation of these pathways through diet has been linked to AHR and allergic airway inflammation(7, 37).…”

Dietary sodium intake and asthma: an epidemiological and clinical review

“…Demissie et al (38) surveyed children selecting 187 cases with a history of asthma or with EIB, along with 145 controls identified from a larger population of 1274 children in Montreal. The children were ranked for salt intake using an unvalidated food questionnaire, and children who had a FEV 1 value >75% of their forced vital capacity (FVC) underwent methacholine challenge for airway responsiveness.…”