title: Arachidonic acid intake and asthma risk in children and adults: a systematic review of observational studies.
abstract: The effect of arachidonic acid (ARA) intake on asthma risk is unclear. The objective of the present review was to systematically evaluate available observational studies on the relationship between ARA exposure and asthma risk in children and adults. A PubMed search was conducted on 22 October 2013 and seventy-three publications were checked against predefined criteria for eligibility. To identify additional eligible publications, potentially relevant articles were searched from bibliographies of articles on ARA and asthma. A total of 2924 citations were scrutinised. Finally, fourteen articles were included. A quality assessment was conducted based on the reporting and methodological quality. A meta-analysis was not conducted; therefore, a qualitative assessment is presented. Three high-, two medium- and ten low-quality studies were reviewed. Eleven studies, including two high- and two medium-quality studies, did not find a significant association between ARA exposure and asthma risk. In contrast, one high-quality study indicated a significant trend toward reducing asthma risk in children with decreasing maternal ARA intake (P trend = 0·025), and one low-quality study reported a significant trend of increasing asthma risk with higher blood ARA levels (P trend = 0·007). In two low-quality studies, asthma patients had significantly lower blood ARA levels than controls (both P < 0·05). These studies did not sufficiently demonstrate any relationships between ARA exposure and asthma risk because of the limited number of studies and their methodological limitations. They seem to suggest that ARA exposure is not consistently associated with asthma risk. Nevertheless, further evidence is required to prove or disprove the association.
authors.affiliation: Department of Social and Preventive Epidemiology, School of Public Health , The University of Tokyo , Tokyo , Japan ; Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Saki
authors.initials: S
authors.lastname: Kakutani
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Kahori
authors.initials: K
authors.lastname: Egawa
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Kayo
authors.initials: K
authors.lastname: Saito
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Horikawa
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Rogi
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawashima
authors.affiliation: Institute for Health Care Science , Suntory Wellness Limited, Osaka , Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shibata
authors.affiliation: Department of Social and Preventive Epidemiology, School of Public Health , The University of Tokyo , Tokyo , Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sasaki
keywords: ARA, arachidonic acid; Asthma; Dietary fatty acids; Epidemiology; Free-living populations; STROBE, Strengthening the Reporting of Observational Studies in Epidemiology; cys-LT, cysteinyl leukotriene