Background Among respiratory diseases, asthma is one of the most burdensome disorder worldwide. Growing evidence disclose gut dysbiosis may contribute to asthma via the gut-lung axis. Constipation can lead to alteration of the gut microflora. The clinical impact of constipation on asthma has not been researched. Therefore, we aim to assess the risk of asthma in constipated patients by a nationwide population-based cohort study. Methods We analyzed 82421 constipated patients and 82421 individuals without constipation between 1999 and 2013 from the Taiwanese National Health Insurance Research Database. Analysis of propensity score was utilized to match age, gender, comorbidities, and medications at a ratio of 1:1. Besides, multiple Cox regression analysis was performed to evaluate the adjusted hazard ratio of asthma. Furthermore, sensitivity tests and a stratified analysis were conducted. Results The incidence of asthma was 10.8 per 1,000 person-years in the constipation group, which was higher than the rate of 5.6 per 1,000 person-years observed in the non-constipation group. After adjustment for age, gender, comorbidities, and medications, constipated patients had a 1.91-fold greater risk of asthma compared to those without constipation (adjusted hazard ratio [aHR]: 1.91 (95% C.I. 1.84-1.99). In subgroup analyses, patients aged 20-39 years had a 2.04-fold highest risk of asthma in the constipation cohort (aHR:2.04, 95% CI, 1.84-2.26). Besides, the severity of constipation is associated with an increased risk of asthma; the aHR was 1.76 (1.69-1.85), 2.15(2.03-2.27), and 2.29(2.10-2.49) for < 3 times, 3-12 times, and ≥12 times of laxatives prescription within one year, respectively. (p<0.001) Moreover, constipated patients had a higher likelihood of asthma, regardless of gender, comorbidities, and medications. Conclusion Constipation relates to a significantly increased risk of asthma. Physicians should be aware of the possibility of asthma in constipated people. Further research is warranted to investigate the possible pathological mechanisms of this association.

Atopic dermatitis (AD) is the chronic relapsing inflammatory skin disorder that affects both in childhood and adulthood. Mounting evidence indicates that gut dysbiosis contributes to AD via the gut-skin axis. Constipation could result in alteration of the gut microflora. The clinical impact of constipation on AD has not been researched. Therefore, we aim to assess the risk of AD in constipated patients by the longitudinal nationwide population-based cohort study. We collected 87015 people with constipation and 87015 patients without constipation between 1999 and 2013 from the Longitudinal Health Insurance Database, which is the subset of Taiwanese National Health Insurance Research Database. Propensity score analysis was administrated to match age, gender, comorbidities, and medications at a ratio of 1:1. Multiple Cox regression analysis was utilized to evaluate the adjusted hazard ratio of AD. In addition, sensitivity tests and a stratified analysis were conducted. The incidence of AD was 4.7 per 1,000 person-years in the constipation group, which was higher than the rate of 2.2 per 1,000 person-years observed in the non-constipation group. After adjustment for age, gender, comorbidities, corticosteroids, and antihistamine, people with constipation had a 2.11-fold greater risk of AD compared to those without constipation (adjusted hazard ratio [aHR]: 2.11 (95% C.I. 1.98-2.24). In subgroup analyses, people aged 12-19 years had a 2.34-fold higher risk of AD in the constipation cohort (aHR; 95% CI, 1.84-2.98). Moreover, people with constipation had a higher likelihood of AD, regardless of gender, and with or without comorbidities, as well as the usage of corticosteroids, and antihistamines. Constipation is connected with a significantly risk factor of AD. Clinicians should be careful of the possibility of AD in people with constipation. Further study is warranted to investigate the possible pathological mechanisms of underlying this relationship.

Background Atopic dermatitis (AD) is the chronic inflammatory disorder that affects both in childhood and adulthood. Mounting evidence indicates that gut dysbiosis contributes to AD via the gut-skin axis. Constipation can result in alteration of the gut microflora. The clinical impact of constipation on AD has not been researched. Therefore, we aim to assess the risk of AD in constipated patients by the population-based cohort study. Methods We collected 87015 constipated people and 87015 people without constipation between 1999 and 2013 from the Taiwanese National Health Insurance Research Database. Propensity score analysis was administrated to match age, gender, comorbidities, and medications at a ratio of 1:1. Multiple Cox regression analysis was utilized to evaluate the adjusted hazard ratio of AD. In addition, sensitivity tests and a stratified analysis were conducted. Results The incidence of AD was 4.7 per 1,000 person-years in the constipation group, which was higher than the rate of 2.2 per 1,000 person-years observed in the non-constipation group. After adjustment for age, gender, comorbidities, corticosteroids, and antihistamine, constipated people had a 2.11-fold greater risk of AD compared to those without constipation (adjusted hazard ratio [aHR]: 2.11 (95% C.I. 1.98-2.24). Moreover, constipated people had a higher likelihood of AD, regardless of gender, comorbidities, as well as the usage of corticosteroids, and antihistamines. Conclusion Constipation is associated with a significantly risk factor of AD. Clinicians should be careful of the possibility of AD in constipated people. Further study is warranted to investigate the possible pathological mechanisms of this relationship.