{
  "abstract": "Introduction More females than ever are taking up shift working. We have previously shown that asthma is more common in night shift workers and female night shift workers in particular are significantly more at risk. Why this is the case is unknown. We aim to investigate further in newly available Our Future Health (OFH) data by examining how these relationships vary by age and by use of hormonal contraception.Methods We are one of the first groups to use the OFH dataset; a large cohort of over 1.7 million participants (17–95 years; 57.2% female; 10% non-White), representative of the UK in terms of ethnicity and age, recently made available for health research. OFH’s large size and greater age and ethnic diversity, compared to other cohorts,make it well-suited to address our objectives. We use logistic regression, adjusted for demographic and lifestyle factors, to describe sex differences in prevalent asthma by shift work status, and explore interactions by age and contraceptive use.Results Compared to female day workers, females working irregular shift work including nights had higher covariate-adjusted odds of asthma ( A; OR: 1.08 (95% CI 1.02–1.15)) whereas this shift pattern was linked to a lower likelihood of asthma in males (OR 0.93 (95% CI 0.87–1.00); sex interaction p-value<0.01). Sex-stratified covariate-adjusted relationships between shift work status and prevalent asthma did not vary significantly across age groups (B), p-interaction: males p=0.07; females p=0.99. In female participants, use of hormonal contraception was associated with higher asthma prevalence when compared to non-users (C; e.g. combined pill, OR 1.09 (95% CI 1.06–1.12)), but use of the combined pill use did not fully explain the relationship between shift-work and prevalent asthma (D).Abstract M17 Figure 1Adjusted odds (95% CI) of asthma. A: By current shift work exposure and stratified by sex. B: By current shift work exposure and stratified by sex and quintiles of age. C: By contraception use. D: By current shift work exposure and stratified by use of the combined pill. All analyses adjusted for age (except for in B), ethnicity, household income, alcohol status and intake, days exercised (walked, moderate and vigorous), length of working week and chronotypeConclusion We confirm that shift work is associated with higher likelihood of asthma in females and show, for the first time, lower likelihood of asthma in male shift workers compared to male day workers. Although contraceptive use was linked to a higher likelihood of asthma, contraceptive use did not explain the higher risk of asthma in female shift workers. Further research is required to understand the basis of observed sex differences.",
  "authors": [
    {
      "affiliations": [
        "Division of Immunology, Immunity to Infection and Respiratory Medicine, University of Manchester, Manchester, UK"
      ],
      "name": "RJ Maidstone"
    },
    {
      "affiliations": [
        "Division of Diabetes, Endocrinology and Gastroenterology, University of Manchester, Manchester, UK"
      ],
      "name": "MK Rutter"
    },
    {
      "affiliations": [
        "Division of Immunology, Immunity to Infection and Respiratory Medicine, University of Manchester, Manchester, UK"
      ],
      "name": "HJ Durrington"
    }
  ],
  "title": "M17 Sex differences in the relationship between shift work status and prevalent asthma in the our future health cohort",
  "uid": "5957afaa-208f-5be5-b24f-22c939356974"
}