Abstract MP040: Chronic Asthma, Rhinosinusitis, and Risk of Type 2 Diabetes Mellitus in Chinese Singaporeans: The Singapore Chinese Health Study
Authors: Mueller Noel T , Koh Woon-Puay , Gross Myron D , Yuan Jian-Min , Pereira Mark A 
Published: July 2021

Introduction:
The role of chronic inflammatory conditions of the respiratory system in the pathogenesis of type 2 diabetes is not well understood. Hypothesis: We investigated the hypothesis that asthma and chronic rhinosinusitis are associated with an increased risk of incident type 2 diabetes in Chinese adults.

Methods:
We used data from the Singapore Chinese Health Study, including Chinese men and women aged 45-74 y, free of cancer, heart disease, stroke, and diabetes at baseline (1993-1998) and followed through 2004. We classified participants according to the presence or absence of self-reported histories of physician-diagnosed asthma or chronic rhinosinusitis (ie, allergic rhinitis and/or sinusitis).

Results:
During an average follow-up of 5.7 years, 2,234 of the 42,842 participants included in the current analyses were diagnosed with type 2 diabetes. Smoking status significantly modified the asthma-diabetes association (Pinteraction= 0.018). After adjustment for potential confounders and BMI, asthma was associated with a 34% increased risk of incident diabetes (HR = 1.34; 95% CI: 1.08, 1.66) in nonsmokers, but asthma was not associated with diabetes in ever smokers. The association was similar for early compared to late onset asthma (see table). Conversely, there was no association between rhinosinusitis and diabetes in non- or ever smokers. The observed associations were not significantly modified by age, physical activity, alcohol intake, or BMI.

Conclusions:
We found a positive association between asthma and incident type 2 diabetes in non-smokers after adjustment for potential confounders and BMI. The observed asthma-diabetes association is consistent with epidemiologic data linking chronic airway inflammation with diabetes risk. This along with a lack of a rhinosinusitis-diabetes association suggests that lower, but not upper, respiratory track inflammation may contribute to the pathology of type 2 diabetes. Our findings serve to improve the targeting of subpopulations at high risk for diabetes.

Table

Hazard ratios (HRs) and 95% CI of type 2 diabetes according to asthma and rhinosinusitis.

No Asthma
Asthma
Asthma diagnosis ≤ age 18
Asthma diagnosis > age 18
No Rhinosinusitis
Rhinosinusitis

Non-smokers (n)
29,765
1,318
585
733
30,151
932

Person-years
169,060
7,396
7,396
7,396
171,139
5,317

Incident diabetes (n)
1,470
88
36
52
1,523
35

Multivariate, HRs (95% CI)
1 (referent)
1.37 (1.11, 1.70)
1.41 (1.02, 1.97)
1.37 (1.02, 1.77)
1 (referent)
0.82 (0.59, 1.15)

Multivariate + BMI, HRs (95% CI)
1 (referent)
1.34 (1.08, 1.66)
1.40 (1.01, 1.95)
1.30 (0.99, 1.72)
1 (referent)
0.86 (0.62, 1.21)

Ever smokers (n)
11,226
533
179
354
11,487
272

Person-years
65,340
3,098
3,098
3,098
66,873
1,565

Incident diabetes (n)
649
27
11
16
668
8

Multivariate, HRs (95% CI)
1 (referent)
0.82 (0.55, 1.20)
1.02 (0.56, 1.85)
0.72 (0.44, 1.18)
1 (referent)
0.51 (0.25, 1.02)

Multivariate + BMI, HRs (95% CI)
1 (referent)
0.80 (0.55, 1.18)
0.93 (0.51, 1.69)
0.73 (0.45, 1.20)
1 (referent)
0.51 (0.25, 1.03)

Models adjusted for year of interview, sex, age, ethnicity, educational level, lifetime second-hand smoke exposure, alcohol intake, physical activity, total energy intake, prevalent hypertension, and baseline BMI (quadratic)