Type 2 diabetes prevalence and incidence among adults in Taiwan during 1999-2004: a national health insurance data set study.
OBJECTIVE
To evaluate annual prevalence and incidence of Type 2 diabetes and to examine possible trends among adults in Taiwan.


METHODS
A retrospective nationwide longitudinal study using the Taiwan National Health Insurance Research Database collected during 1999-2004. Adult patients aged > or = 20 years old with prevalent and incident Type 2 diabetes were identified using ICD-9-CM diagnostic codes. Age-specific and age-direct-standardized annual incidence and prevalence were calculated to describe their trends in different gender and age group and compared using Poisson regression.


RESULTS
During the study years, the age-standardized prevalence of Type 2 diabetes increased from 4.7 to 6.5% for men and from 5.3 to 6.6% for women. The increasing trends in prevalence were significant and higher among people aged < 40 and > or = 80 years. The age-standardized incidence rates of Type 2 diabetes per 1000 person-years were approximately 7.6 and remain stable for men, but decreasing from 7.7 to 6.9 for women. However, the incidence increased significantly in younger adults aged < 40 years whose relative incidence (RI with 95% confidence interval) was 1.31 (1.20-1.42) for men and 1.04 (1.01-1.08) for women. The incidence trends for people aged > or = 40 years were decreased for men and women. The differences in incidence trends between age groups and between genders were all statistically significant (all P < 0.001).


CONCLUSIONS
This study demonstrated a substantial increasing trend in Type 2 diabetes prevalence during 1999-2004 among adults in Taiwan. Despite the incidence decreased in older people, young men aged 20-40 years were most susceptible to higher incidence of Type 2 diabetes.
Chang
C H
CH
Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Shau
W Y
WY
Jiang
Y D
YD
Li
H Y
HY
Chang
T J
TJ
Sheu
W H-H
WH
Kwok
C F
CF
Ho
L T
LT
Chuang
L M
LM
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009313:National Health Programs; D015995:Prevalence; D012189:Retrospective Studies; D013223:Statistics as Topic; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult