Trends in the prevalence of intellectual disability among children in Taiwan.
Taiwan’s mild-ID caseload swelled 64% in a decade, signaling diagnostic drift rather than a surge in severe disability.
01Research in Context
What this study did
The team pulled every child ID record in Taiwan’s national registry.
They counted how many kids had mild versus severe ID each year from 2000 to 2011.
No new data were collected; they simply tracked the same diagnosis codes over time.
What they found
Mild ID cases rose from 3.60 to 5.91 per 1,000 children.
Severe ID counts stayed flat.
The 64% jump came almost entirely from the mild group.
How this fits with other research
Corrigan et al. (1998) mapped genetic causes in Taiwanese kids with ID. Their old snapshot gives a baseline before the rise began.
Chiang et al. (2013) show these same kids now average 20 outpatient visits and triple the medical cost of peers. More mild cases means more service load.
Chang et al. (2014) found only 11% of youth with ID receive outpatient PT despite universal insurance. The registry surge widens this gap.
Hsu et al. (2014) saw psychotropic prescribing climb in the same years. More mild-ID diagnoses could explain part of that trend.
Why it matters
The jump is in mild ID, not severe. That points to better detection, broader criteria, or families seeking services—not a true epidemic. When you see a new mild-ID client, ask: would this child have been counted ten years ago? Use the answer to set realistic goals, plan for high healthcare use, and check if PT or behavioral services are already in place.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Screen new mild-ID clients for untreated medical issues; they likely have triple the healthcare needs of typical peers.
02At a glance
03Original abstract
BACKGROUND: Intellectual disability (ID) is a major developmental disability. However, data on changes in the prevalence over time at the national level are limited. METHOD: Using data from the national disability registry, we conducted an ecological study to evaluate the time trends of ID among children in Taiwan. We calculated the prevalence of ID by age, sex and severity, from 2000 to 2011, and assessed the time trends. RESULTS: During the study period, the overall prevalence of ID in children aged 3-17 years increased from 3.60 to 5.91 per 1000 (β = 0.22, P < 0.001, r2 = 0.97). The prevalence of mild ID (MID, intelligence quotient: 50-69) increased from 1.30 to 3.60 per 1000 (β = 0.21, P < 0.001, r2 = 0.98). However, the prevalence of severe ID (SID, intelligence quotient: <50) was relatively constant, between 2.22 and 2.38 per 1000 (β = 0.01, P = 0.076, r2 = 0.96). Boys had a higher prevalence than girls, and the average boy-to-girl prevalence ratio was 1.42 for MID and 1.31 for SID. The boy-to-girl prevalence ratios of MID and SID decreased over time (β = -0.01, P < 0.001, r2 = 0.99 for MID; β = -0.01, P < 0.001, r2 = 1.00 for SID). CONCLUSION: The prevalence of ID in Taiwanese children increased from 2000 to 2011 and was largely attributable to increases in MID. Boys had a higher prevalence of ID and were more likely to have MID.
Journal of intellectual disability research : JIDR, 2023 · doi:10.1111/jir.12998