We have investigated the relationship between decline in lung function and dietary intakes of magnesium, vitamin C, and other antioxidant vitamins in a general population cohort in Nottingham, United Kingdom. In 1991, we measured dietary intake by semiquantitative food frequency questionnaire, forced expiratory volume in 1 second (FEV1), and respiratory symptoms in a cross-sectional survey of 2,633 adults aged 18-70. Nine years later we repeated these measures in 1,346 of these individuals. In cross-sectional analyses, after adjustment for smoking and other confounders, higher intakes of vitamin C and magnesium, but not vitamins A or E, were associated with higher levels of FEV1 in both 1991 and 2000. In longitudinal analysis with adjustment for confounders, decline in FEV1 between 1991 and 2000 was lower amongst those with higher average vitamin C intake by 50.8 ml (95% confidence interval, 3.8-97.9) per 100 mg of vitamin C per day, but was unrelated to magnesium intake. There was no relationship between decline in FEV1 and intake of vitamins A or E. This study suggests that a high dietary intake of vitamin C, or of foods rich in this vitamin, may reduce the rate of loss of lung function in adults and thereby help to prevent chronic obstructive pulmonary disease.

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There are few validated methods of measuring dietary fatty acid intake that are suitable for epidemiological research. The purpose of the present study was to develop and validate a food-frequency questionnaire (FFQ) developed to measure individual dietary fatty acid intakes against 7 d weighed dietary records, in a sample of thirty-one healthy adult volunteers. The FFQ was based on a previously validated questionnaire (DIETQ; Tinuviel Software, Warrington, Ches., UK), adapted to include greater detail on those foods from which the majority of dietary fatty acids are obtained. The FFQ and weighed records were analysed using food nutrient data from McCance and Widdowson's Food Composition Tables, supplemented with a food fatty acid content database (Foodbase, London, UK). Results from the two dietary assessment methods were compared by correlation coefficients and limits of agreement. The mean intake of individual fatty acids tended to be lower when assessed by FFQ. Correlation coefficients comparing unadjusted individual fatty acid intakes assessed by FFQ and weighed records ranged from 0·29 for 18 : 1n-9 to 0·71 for 20 : 4n-6. Adjusting for energy intake tended to increase the correlation coefficients between saturated fatty acids and decrease those between unsaturated fatty acids. In conclusion, this food-frequency method provides reliable estimates of dietary intake of many individual fatty acids for use in epidemiological studies.

These findings suggest that dietary omega-3 fatty acids do not play a major role in protecting against asthma, and that higher levels of erythrocyte membrane linoleic acid are associated with a lower risk of asthma.

Amino acids contribute to various anti-oxidant and immunological activities relevant to asthma pathogenesis, raising the possibility that differences in amino acids may be involved in asthma aetiology. The authors hypothesised that cystine reduces the risk of asthma via glutathione metabolism. Methionine, glutamine, glutamic acid and glycine may have potential protective effects, whilst arginine, phenylalanine and tryptophan may have adverse effects in asthma.Fasting plasma levels of amino acids were compared in a case-control study. A total of 89 adults, aged 18-65 yrs, with asthma controlled by inhaled corticosteroids, were recruited from a volunteer database and local primary care registers, and compared with 89 controls individually matched for age, sex and primary care centre.Contrary to the primary hypothesis, cases had higher fasting plasma cystine levels than controls, and there was no difference between cases and controls in any of the other amino acids tested, with the exception of plasma glycine, which was associated with a strongly reduced risk of asthma (odds ratio for the highest tertile compared to lowest 0.30 (95% confidence interval (0.11-0.82)).This study negates the hypothesis that higher fasting plasma cystine levels have a protective effect on the risk of asthma, although the inverse correlation with plasma glycine deserves further investigation.

ImportanceWhether selective decontamination of the digestive tract (SDD) reduces mortality in critically ill patients remains uncertain.ObjectiveTo determine whether SDD reduces in-hospital mortality in critically ill adults.Design, Setting, and ParticipantsA cluster, crossover, randomized clinical trial that recruited 5982 mechanically ventilated adults from 19 intensive care units (ICUs) in Australia between April 2018 and May 2021 (final follow-up, August 2021). A contemporaneous ecological assessment recruited 8599 patients from participating ICUs between May 2017 and August 2021.InterventionsICUs were randomly assigned to adopt or not adopt a SDD strategy for 2 alternating 12-month periods, separated by a 3-month interperiod gap. Patients in the SDD group (n = 2791) received a 6-hourly application of an oral paste and administration of a gastric suspension containing colistin, tobramycin, and nystatin for the duration of mechanical ventilation, plus a 4-day course of an intravenous antibiotic with a suitable antimicrobial spectrum. Patients in the control group (n = 3191) received standard care.Main Outcomes and MeasuresThe primary outcome was in-hospital mortality within 90 days. There were 8 secondary outcomes, including the proportion of patients with new positive blood cultures, antibiotic-resistant organisms (AROs), and Clostridioides difficile infections. For the ecological assessment, a noninferiority margin of 2% was prespecified for 3 outcomes including new cultures of AROs.ResultsOf 5982 patients (mean age, 58.3 years; 36.8% women) enrolled from 19 ICUs, all patients completed the trial. There were 753/2791 (27.0%) and 928/3191 (29.1%) in-hospital deaths in the SDD and standard care groups, respectively (mean difference, −1.7% [95% CI, −4.8% to 1.3%]; odds ratio, 0.91 [95% CI, 0.82-1.02]; P = .12). Of 8 prespecified secondary outcomes, 6 showed no significant differences. In the SDD vs standard care groups, 23.1% vs 34.6% had new ARO cultures (absolute difference, −11.0%; 95% CI, −14.7% to −7.3%), 5.6% vs 8.1% had new positive blood cultures (absolute difference, −1.95%; 95% CI, −3.5% to −0.4%), and 0.5% vs 0.9% had new C difficile infections (absolute difference, −0.24%; 95% CI, −0.6% to 0.1%). In 8599 patients enrolled in the ecological assessment, use of SDD was not shown to be noninferior with regard to the change in the proportion of patients who developed new AROs (−3.3% vs −1.59%; mean difference, −1.71% [1-sided 97.5% CI, −∞ to 4.31%] and 0.88% vs 0.55%; mean difference, −0.32% [1-sided 97.5% CI, −∞ to 5.47%]) in the first and second periods, respectively.Conclusions and RelevanceAmong critically ill patients receiving mechanical ventilation, SDD, compared with standard care without SDD, did not significantly reduce in-hospital mortality. However, the confidence interval around the effect estimate includes a clinically important benefit.Trial RegistrationClinicalTrials.gov Identifier: NCT02389036