Background Cured meat intake—a recent carcinogenic factor—may increase the risk of COPD, but its association with asthma remains unknown. Though body mass index (BMI) is a likely risk factor for asthma, its role in the diet–asthma association as a mediator has never been studied. We investigated the association between cured meat intake and worsening asthma symptoms in adults, and the role of BMI as a potential mediator. Methods Using data from the French prospective EGEA study (baseline: 2003–2007; follow-up: 2011–2013), we applied a mediation analysis in the counterfactual framework, a marginal structural model (MSM), to estimate the direct effect of baseline cured meat intake (<1, 1–3.9, ≥4 servings/week) on change in asthma symptom score (worsening or not), and the indirect effect mediated by BMI. Results Among the 971 participants (mean age 43 years; 49% men; 42% with asthma), 20% reported worsening asthma symptoms during the mean follow-up time of 7 years. Using the MSM, we reported a positive direct effect of cured meat intake on worsening asthma symptoms (multivariable OR=1.76, 95% CI 1.01 to 3.06 for ≥4 vs <1 serving/week). We also reported an indirect effect mediated by BMI (OR=1.07; 95% CI 1.01 to 1.14), accounting for 14% of the total effect. Conclusions Higher cured meat intake was associated with worsening asthma symptoms over time, through a direct effect and to a lesser extent an effect mediated by BMI. This research extends the effect of diet on asthma in adults.

It has been hypothesised that increased asthma prevalence in westernised countries is associated with changes in lifestyle factors, including a poorer diet. However, little is known regarding the association between diet quality and asthma. In the diet–asthma association, the role of BMI as a potential mediator needs clarification; moreover, potential effect modification by non-diet sources of oxidants, such as smoking, merits investigation. We investigated the association between diet quality and change in asthma symptoms, as well as assessed effect modification by smoking, while accounting for BMI as a potential mediator. Using data from the French prospective Epidemiological study on the Genetics and Environment of Asthma study, we assessed diet quality using the Alternate Healthy Eating Index 2010 (AHEI-2010) at baseline and change in asthma symptoms (stable (reference), worsening, improved; mean follow-up time: 7 years). Mediation analysis was used to disentangle total and direct effects and the indirect effect mediated by BMI. The analyses included 969 adults (mean age 43 years; 49 % men; 42 % ever asthma). We observed a significant interaction between smoking and AHEI-2010 on change in asthma symptoms (P_{for interaction}=0·04). Among never smokers (n 499), we observed a positive total effect (multivariable OR 1·39; 95 % CI 1·07, 1·80) and a positive direct effect (OR 1·41; 95 % CI 1·09, 1·80) of the AHEI-2010 (per ten-point increment) on improved symptoms. No indirect effect mediated through BMI was observed (OR 0·99; 95 % CI 0·91, 1·07). Among former and current smokers, all effects were statistically non-significant. Better diet quality was associated with improved asthma symptoms over time in never smokers, independently of BMI.

Although vaginal microbiota (VM) may interact with human papillomavirus (HPV) infection and clearance, longitudinal data remain very limited. We aimed to investigate the association between VM at baseline and the clearance of high-risk HPV (HR-HPV) infection within 12 months. Cervical swabs were collected at diagnosis from 85 patients with HR-HPV infection and histologically confirmed cervical lesions, including cervicitis, low-grade squamous intraepithelial lesion and high-grade squamous intraepithelial lesion. Microbiome analysis was performed using 16S rRNA gene sequencing. Among the 73 women included in the analyses, HPV clearance was observed in 58.9% of the patients within 12 months. No significant difference was observed between the HPV-cleared and HPV-uncleared groups regarding age, disease stage, HPV subtype, VM community state types, and VM diversity (α and β). Women with the depletion of enterococcus ASV_62 and enrichment in Lactobacillus iners at baseline were less likely to have HPV clearance at month 12. Further analysis revealed a significant negative association between high abundance of L. iners and HPV clearance in patients who received non-operative treatment (OR = 3.94, p = 0.041), but not in those who received operative treatment (OR = 1.86, p = 0.660). Our findings provide new evidence for the potential role of VM in the persistent HR-HPV infections.

The prevalence of asthma has nearly doubled over the last decades. Twentieth century changes in environmental and lifestyle factors, including changes in dietary habits, physical activity and the obesity epidemic, have been suggested to play a role in the increase of asthma prevalence and uncontrolled asthma worldwide. A large body of evidence has suggested that obesity is a likely risk factor for asthma, but mechanisms are still unclear. Regarding diet and physical activity, the literature remains inconclusive. Although the investigation of nutritional factors as a whole (i.e., the “diet, physical activity and body composition” triad) is highly relevant in terms of understanding underlying mechanisms, as well as designing effective public health interventions, their combined effects across the life course has not received a lot of attention. In this review, we discuss the state of the art regarding the role of nutritional factors in asthma, for each window of exposure. We focus on the methodological and conceptual challenges encountered in the investigation of the complex time-dependent interrelations between nutritional factors and asthma and its control, and their interaction with other determinants of asthma. Lastly, we provide guidance on how to address these challenges, as well as suggestions for future research.