Introduction:
South Asians develop type 2 diabetes (T2D) at younger ages. This study evaluated how age at T2D diagnosis impacts risks of all-cause mortality, cardiovascular (CVD) mortality, non-fatal CVD events, and years of life lost (YLL).
Methods:
- Population: 21,861 CARRS cohort participants.
- T2D Definition: Based on self-report, treatment, or lab criteria [Fasting blood glucose (FPG) ≥126 mg/dL, 2-hour post-meal glucose (2-h PG) >200 mg/dL, glycated hemoglobin (HbA1c) ≥6.5%].
- Groups by Age at Diagnosis: 20–29, 30–39, 40–59, ≥60 years.
- Analysis: Cox regression (adjusted for age, sex, BMI, smoking, education, BP, and cholesterol); YLL calculated using India’s Individual Annuitant Mortality Table.
Results:
- T2D Prevalence: 6,396 participants (5,295 prevalent; 181 incident).
- Follow-up: 132,293 person-years over 14 years.
- Outcomes: 2,121 deaths (809 from CVD); 336 non-fatal CVD events.
|
Outcome |
No diabetes, n=15,465 |
T2D 20–29y,n=268 (4.2%) |
T2D 30–39n=1,194 (18.7%) |
T2D 40–59y, n=3,831 (59.9%) |
T2D ≥60y, n=1,103 (17.2%) |
|
Total Mortality |
|||||
|
No. of events |
951 |
15 |
109 |
617 |
429 |
|
Mortality rate (/1000 PY) |
10.7 |
8.4 |
13.2 |
23.4 |
59.8 |
|
HR [95% CI]a |
Ref |
2.0 [1.7–2.3] |
1.9 [1.7–2.1] |
1.4 [1.3–1.5] |
1.1 [1.0–1.1] |
|
HR [95% CI]b |
Ref |
2.2 [1.2–3.8] |
2.0 [1.6–2.5] |
1.4 [1.2–1.6] |
0.9 [0.8–1.1] |
|
CVD Mortality |
|||||
|
No. of events |
278 |
3 |
46 |
297 |
185 |
|
Mortality rate (/1000 PY) |
3.1 |
1.7 |
5.6 |
11.3 |
25.8 |
|
HR [95% CI]a |
Ref |
2.7 [2.2–3.4] |
3.1 [2.7–3.6] |
2.2 [2.0–2.3] |
1.3 [1.2–1.5] |
|
HR [95% CI]b |
Ref |
1.9 [0.6–6.0] |
2.7 [1.9–4.0] |
2.1 [1.7–2.5] |
1.1 [0.9–1.4] |
|
Non-fatal CVD Events |
|||||
|
No. of events |
130 |
3 |
25 |
132 |
46 |
|
Incidence rate (/1000 PY) |
1.5 |
1.7 |
3.1 |
5.1 |
6.4 |
|
HR [95% CI]a |
Ref |
2.4 [1.7–3.4] |
2.1 [1.6–2.7] |
2.3 [2.0–2.6] |
1.4 [1.1–1.8] |
|
HR [95% CI]b |
Ref |
1.3 [0.3–5.5] |
2.4 [1.5–3.9] |
2.1 [1.6–2.8] |
1.1 [0.7–1.7] |
PY = person-years; HR = hazard ratio; CVD = cardiovascular disease a: Adjusted for age and sex, b: Adjusted for age, sex, education, smoking, BMI, systolic blood pressure, and total cholesterol
Conclusion:
Younger age at T2D onset is associated with higher risks of all-cause and CVD mortality, non-fatal CVD events, and more life years lost. The burden is greatest for those diagnosed before age 40, emphasizing the need for early detection and management in South Asians.
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