Factors associated with villus atrophy in symptomatic coeliac disease patients on a gluten-free diet

BACKGROUND

Duodenal injury persists in some coeliac disease patients despite gluten-free diet, and is associated with adverse outcomes.

AIM

To determine the prevalence and clinical risk factors for persistent villus atrophy among symptomatic coeliac disease patients.

METHODS

A nested cross-sectional analysis was performed on coeliac disease patients with self-reported moderate or severe symptoms while following a gluten-free diet, who underwent protocol-mandated duodenal biopsy upon enrolment in the CeliAction clinical trial. Demographic factors, symptom type, medication use, and serology were examined to determine predictors of persistent villus atrophy.

RESULTS

Of 1345 symptomatic patients, 511 (38%, 95% CI, 35-41%) were found to have active coeliac disease with persistent villus atrophy, defined as average villus height to crypt depth ratio ≤2.0. On multivariable analysis, older age (OR, 5.1 for ≥70 vs. 18-29 years, 95% CI, 2.5-10.4) was a risk factor while longer duration on gluten-free diet was protective (OR, 0.37, 95% CI, 0.24-0.55 for 4-5.9 vs. 1-1.9 years). Villus atrophy was associated with use of proton-pump inhibitors (PPIs; OR, 1.6, 95% CI, 1.1-2.3), non-steroidal anti-inflammatory drugs (NSAIDs; OR, 1.64, 95% CI, 1.2-2.2), and selective serotonin reuptake inhibitors (SSRIs; OR, 1.74, 95% CI, 1.2-2.5). Symptoms were not associated with villus atrophy after adjusting for covariates. Conclusions A majority of symptomatic coeliac disease patients did not have active disease on follow-up histology. Symptoms were poorly predictive of persistent mucosal injury. The impact of NSAIDs, PPIs, and SSRIs on mucosal healing in coeliac disease warrants further study.

Systematic review with meta-analysis: the prevalence of coeliac disease in patients with osteoporosis

BACKGROUND

Earlier studies have produced highly varying risk estimates for the prevalence of coeliac disease (CD) in osteoporosis.

AIMS

To investigate the prevalence of CD among individuals with osteoporosis.

METHODS

We conducted a systematic review of articles published in PubMed, Medline or EMBASE through May 2017 to identify studies looking at prevalence of CD in patients with osteoporosis. Search terms included "coeliac disease" combined with "fractures", "bone disease", "bone density", "densitometry", "osteoporos*", "osteomal*", "osteodys" or "dexa" or "dxa" or "skelet". Non-English papers with English-language abstracts were included. We used fixed-effects inverse variance-weighted models, and tested heterogeneity through subgroup analysis as well as through meta-regression.

RESULTS

We identified eight relevant studies, comprising data from 3188 individuals with osteoporosis. Of these, 59 individuals (1.9%) had CD. A weighted pooled analysis demonstrated biopsy-confirmed CD in 1.6% (95% CI = 1.1%-2.0%) of individuals with osteoporosis. The heterogeneity was moderate (I2  = 40.1%), and influenced by the underlying CD prevalence in the general population. After adding four studies (n = 814) with CD defined as positive tissue transglutaminase or endomysial antibodies, the pooled prevalence was comparable (1.6%; 95% CI = 1.2%-2.0%).

CONCLUSIONS

About 1 in 62 individuals with osteoporosis, or 1.6%, have biopsy-verified CD. This prevalence is comparable to that in the general population. These findings argue against routinely screening patients with osteoporosis for CD, which is contrary to current guideline recommendations. Additional studies are needed to determine the true utility of such screening programs.

Color perception through atmospheric haze

The radiance of most objects seen at a distance through the atmosphere is dominated by scattered light of a blue hue that should make the landscape appear predominately blue. However, common experience shows that people can see colors at a distance. A possible explanation of this paradox is that the visual system splits the light into a haze layer and the background landscape. A straightforward mathematical description of this splitting explains the results of a color matching study in the Great Smoky Mountains National Park. In this study, hues of objects seen through haze were found to be constant with changes in optical depth while colorfulness decreased exponentially.

Obesity alters the topographical distribution of ventilation and the regional response to bronchoconstriction

Obesity is associated with reduced operating lung volumes that may contribute to increased airway closure during tidal breathing and abnormalities in ventilation distribution. We investigated the effect of obesity on the topographical distribution of ventilation before and after methacholine-induced bronchoconstriction using single-photon emission computed tomography (SPECT)-computed tomography (CT) in healthy subjects. Subjects with obesity ( n = 9) and subjects without obesity ( n = 10) underwent baseline and postbronchoprovocation SPECT-CT imaging, in which Technegas was inhaled upright and followed by supine scanning. Lung regions that were nonventilated (Ventnon), low ventilated (Ventlow), or well ventilated (Ventwell) were calculated using an adaptive threshold method and were expressed as a percentage of total lung volume. To determine regional ventilation, lungs were divided into upper, middle, and lower thirds of axial length, derived from CT. At baseline, Ventnon and Ventlow for the entire lung were similar in subjects with and without obesity. However, in the upper lung zone, Ventnon (17.5 ± 10.6% vs. 34.7 ± 7.8%, P < 0.001) and Ventlow (25.7 ± 6.3% vs. 33.6 ± 5.1%, P < 0.05) were decreased in subjects with obesity, with a consequent increase in Ventwell (56.8 ± 9.2% vs. 31.7 ± 10.1%, P < 0.001). The greater diversion of ventilation to the upper zone was correlated with body mass index ( rs = 0.74, P < 0.001), respiratory system resistance ( rs = 0.72, P < 0.001), and respiratory system reactance ( rs = −0.64, P = 0.003) but not with lung volumes or basal airway closure. Following bronchoprovocation, overall Ventnon increased similarly in both groups; however, in subjects without obesity, Ventnon only increased in the lower zone, whereas in subjects with obesity, Ventnon increased more evenly across all lung zones. In conclusion, obesity is associated with altered ventilation distribution during baseline and following bronchoprovocation, independent of reduced lung volumes.

NEW & NOTEWORTHY Using ventilation SPECT-computed tomography imaging in healthy subjects, we demonstrate that ventilation in obesity is diverted to the upper lung zone and that this is strongly correlated with body mass index but is independent of operating lung volumes and of airway closure. Furthermore, methacholine-induced bronchoconstriction only occurred in the lower lung zone in individuals who were not obese, whereas in subjects who were obese, it occurred more evenly across all lung zones. These findings show that obesity-associated factors alter the topographical distribution of ventilation.