Methane gas in breath test is associated with non-alcoholic fatty liver disease.

Although the associations between a patient's body mass index (BMI) and metabolic diseases, as well as their breath test results, have been studied, the relationship between breath hydrogen/methane levels and metabolic diseases needs to be further clarified. We aimed to investigate how the composition of exhaled breath gases relates to metabolic disorders, such as diabetes mellitus, dyslipidemia, hypertension, and nonalcoholic fatty liver disease (NAFLD), and their key risk factors. An analysis was performed using the medical records, including the lactulose breath test (LBT) data of patients who visited the Ajou University Medical Center, Suwon, Republic of Korea, between January 2016 and December 2021. The patients were grouped according to four different criteria for LBT hydrogen and methane levels. Of 441 patients, 325 (72.1%) had positive results for methane only (hydrogen < 20 parts per million [ppm] and methane ⩾ 3 ppm). BMIs and NAFLD prevalence were higher in patients with only methane positivity than in patients with hydrogen and methane positivity (hydrogen ⩾ 20 ppm and methane ⩾ 3 ppm). According to a multivariate analysis, the odds ratio of only methane positivity was 2.002 (95% confidence interval [CI]: 1.244-3.221,P= 0.004) for NAFLD. Our results demonstrate that breath methane positivity is related to NAFLD and suggest that increased methane gas on the breath tests has the potential to be an easily measurable biomarker for NAFLD diagnosis.

The effect of job stress and lifestyle on blood lipid levels in male aircrew personnel.

INTRODUCTION: [corrected] Cardiovascular disease has the potential to lead to sudden in-flight incapacitation and permanent grounding. The aims of this study are to examine the relationships between lifestyle, job stress and blood lipid levels of male aircrew personnel of a Korean airline and to identify which factors influence their hyperlipidemia. METHODS: Two hundred sixteen male aircrew personnel completed a questionnaire by self-report and consented to participate in the study. The questionnaire collected data related to job stress, life style, serum cholesterol levels and general characteristics of the aircrew. The cholesterol levels of the subjects were collected from their most recent health check-up records. Subjects were divided into two groups (the desirable group and the risk group) based on their serum cholesterol level, 200 mg/dl. RESULTS: Mean age and marital status were significantly different between the two groups. More subjects in the risk group had habits of eating high lipid foods, while more subjects in the desirable group exercised more frequently than the risk group. In logistic regression analysis, after controlling age and marital status, types of working situation (domestic duty or international duty, odds ratio=.390, p=.018), diet (odds ratio=.429, p=.037), and exercise (odds ratio=.320, p=.055) were influencing factors on aircrew's serum cholesterol levels. CONCLUSIONS: The cholesterol level of aircrew personnel is closely related to their lifestyle, such as lipid diet and exercise. The type of work situations, e.g. staying in an airplane for long periods of time or staying abroad, may influence these diet patterns and exercise habits.