Epidemiology of Type 2 Diabetes with Community-based Longitudinal Cohort
Date Issued
2011
Date
2011
Author(s)
Hsu, Bih-Tsuen
Abstract
Background: Type 2 diabetes and its associated complications are major contributions to deaths in developed countries. It also causes serious medical burden in society. Therefore, the understanding of the epidemiological profile of type 2 diabetes plays important role in medical source allocation and planning. There is lacking long-term longitudinal and community-based study in the literatures. The aim of the current study was to investigate the prevalence, incidence, and risk factors for type 2 diabetes based on Keelung Community-based Integrated Screening (KCIS).
Materials and Methods: The study population was from the attendee of KCIS, which targeted at residents in Keelung and aged 20 years or above with screening for three chronic diseases and five cancers. In addition to biochemical examination, information of life style, personal history, and family history were collected with a structured questionnaire. A total of 259,875 visits were made by 107,501 subjects between 2000 and 2009 (Male 39.7%, Female: 60.3%), covering 37.1% population aged 20 years and above in Keelung.
In the KCIS program, type 2 diabetes was ascertained with fasting glucose >=126 mg/dl or self-report. In addition, for those with elevated fasting glucose but not reached the level of type 2 diabetes (110-125 mg/dl before 2005 and 100-125 mg/dl after 2006) were referred for OGTT (Oral Glucose Tolerance test) to identify cases of IGT (Impaired glucose tolerance) or type 2 diabetes.
This thesis reports the age- and gender-specific prevalence and incidence of IGT and type 2 diabetes. Age-standardized figures were calculated in the light of 2000 World standard population. Logistic regression models and Poisson regression model were used to identify risk factors for the prevalence and the incidence of type 2 diabetes, respectively. Proportional odds models were used to identify risk factors for IGT and type 2 diabetes treating as different disease status simultaneously. Missing complete at random and missing at random were applied to implement the missing values of disease status for those refusing OGTT referral.
Results: Among the 107,501 subjects in the KCIS program, 52% received more than one screening. The were 4% needed to refer for OGTT before 2005, and 12% after 2006. The referral rates were 40.2% before 2005 and 54.0% after 2006. The proportions of IGT and type 2 diabetes among those referred were 34% and 29% before 2005 and 34% and 18% after 2006.
In Keelung, the crude prevalence of type 2 diabetes was 8.6% (male: 10.1%, female 7.7%), increasing with advancing age. The age-standardized figure was 6.95% (7.7% for male and 6.53 for female). For IGT, the age-standardized figure was 0.51% (male 0.51%, female 0.40%). With adjustment in the light of MCAR method, the age standardized prevalence was 7.6% for type 2 diabetes, and 1.3% for IGT. The figures were similar with adjustment in the light of MAR method.
Significant risk factors affecting prevalence of type 2 diabetes included age (OR=1.048, 95%CI: 1.046-1.05), male(OR=1.06, 95%CI: 1.01-1.11), elevated BMI(OR=1.20, 95%CI:1.14-1.28), hypertension(OR=1.70, 95%CI:1.61-1.79), betel quid chewing (OR=1.16, 95%CI:1.02-1.32), central obesity (OR=1.81, 95%CI:1.71-1.92), elevated cholesterol (OR=0.79, 95%CI:0.73-0.87), elevated triglyceride(OR=2.40, 95%CI: 2.28-2.52), and anti-HCV(OR=1.16, 95%CI:1.04-1.30) in the multivariate logistic regression model. The proportional odds model found similar risk factors for IGT and type 2 diabetes.
The crude incidence for type 2 diabetes was 1.58% (male: 2.01%, female: 1.37%). The standardized incidence for type 2 diabetes was 1.087% (male 1.295%, female: 0.983). The transition rate was 0.83% from normal to IGT, 1.33% from normal to type 2 diabetes, 17.46% from IGT to type 2 diabetes, but as high as up to 35% for regression from IGT to normal.
Factors affecting the incidence of type 2 diabetes include age(RR=1.035, 95%CI: 1.032-1.038), elevated BMI (RR=1.57, 95%CI: 1.45-1.71), hypertension (RR=1.46, 95%CI: 1.36-1.57), smoking (RR=1.16, 95%CI: 1.06-1.28), betel quid chewing (RR=1.31, 95%CI:1.07-1.60), central obesity (1.75, 95%CI: 1.61-1.91), elevated cholesterol (RR=1.28, 95%CI: 1.11-1.48), elevated triglyceride (RR=1.80, 95%CI: 1.67-1.93), anti HCV (RR=1.27, 95%CI: 1.08-1.49) in the multivariable Poisson regression model.
Conclusion: This study is one of the few studies investigating the epidemiological profile for incidence and prevalence of type 2 diabetes with longitudinal and community-based study. The results of study are anticipated to aid public health decision-makers.
Subjects
Diabetes Mellitus
Oral Glucose Tolerance test
Community-based
Impaired glucose tolerance
Impaired Fasting Glucose
pre-diabetes
prevalence
incidence
risk factor.
SDGs
Type
thesis
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