**Background:** Non-communicable diseases (NCDs) account for 71% of all deaths worldwide, with 85% of premature NCD deaths occurring in low- and middle-income countries. In India, NCDs caused approximately 65% of all deaths in 2019, driven largely by rising hypertension and diabetes. Kerala, a southern Indian state, ranks first in India's SDG Index but has paradoxically high morbidity levels due to NCD burden. Education is considered a key socioeconomic predictor of hypertension and diabetes, yet no prior Indian studies had specifically examined educational inequalities in these conditions. This study aimed to assess educational inequalities in both measured and self-reported high blood pressure (BP) and high blood glucose (BG) in Kerala.
**Methods:** Data were drawn from the fifth round of India's National Family Health Survey (NFHS-5), conducted 2019–2021, which used a two-stage stratified sampling design. The analysis included 36,526 individuals aged 15+ from Kerala, of whom 32,250 completed BP measurement and 31,917 completed BG measurement. BP was measured three times using an Omron monitor (average of last two readings; high BP defined as ≥140 mmHg systolic or ≥90 mmHg diastolic or current antihypertensive medication). Random BG was measured using Accu-Chek Performa (high BG defined as >140 mg/dL). Education was classified into four categories: no education, primary (≤5 years), secondary (6–12 years), and higher (>12 years). Statistical analyses included descriptive statistics, logistic regression (adjusted for age, sex, marital status, residence, religion, caste, wealth, alcohol, tobacco, and health insurance), and complex inequality measures: Slope Index of Inequality (SII) for absolute inequality and Relative Concentration Index (RCI) for relative inequality.
**Key Results:** The sample was 53.2% female, 68.2% married, and over half aged 45+. Educational distribution was: 4.6% no education, 13.6% primary, 60.7% secondary, and 21.1% higher. Overall measured prevalence was 32.1% for high BP and 22.5% for high BG; self-reported prevalence was 20.1% and 14.7%, respectively. A clear educational gradient was observed: measured high BP prevalence was 57.7% among those with no education versus 17.6% among those with higher education (40 percentage point gap). For self-reported high BP, the gap was 30.9 percentage points (40.8% vs 9.9%). Measured high BG showed 32.5% prevalence in no-education group versus 12.9% in higher education; self-reported high BG was 22.7% versus 8.1%. After full adjustment, those with no education had 56% greater odds of measured high BP (AOR 1.56; 95% CI 1.31–1.86) and 29% greater odds of self-reported high BP (AOR 1.29; 95% CI 1.06–1.55) compared with higher education. For BG, no significant association was found between no education and measured high BG (AOR 1.16; 95% CI 0.98–1.39) or self-reported high BG (AOR 1.02; 95% CI 0.82–1.26). Complex inequality measures confirmed these patterns: measured high BP showed the largest absolute inequality (SII −45.4%; 95% CI −47.3% to −43.4%) and relative inequality (RCI −26.6%; 95% CI −27.9% to −25.3%). Self-reported high BP had lower but still substantial inequality (SII −34.5%; 95% CI −36.3% to −32.7%; RCI −19.0%; 95% CI −20.1% to −17.9%). For BG, measured values showed SII −26.6% (95% CI −28.6% to −24.7%) and RCI −15.7% (95% CI −16.9% to −14.5%), while self-reported values showed SII −20.6% (95% CI −22.3% to −18.8%) and RCI −11.5% (95% CI −12.5% to −10.5%). All negative values indicate concentration of morbidity among the least educated.
**Clinical Implications:** The study reveals substantial 'hidden' educational inequalities in NCD risk factors in Kerala, with measured indicators showing larger disparities than self-reported ones. This suggests that self-reported data alone may underestimate true inequality burdens. The findings support continued and expanded population-based screening programs, particularly for less-educated groups who bear disproportionate NCD risk. The authors recommend that primary and secondary prevention options be made more widely available to populations with lower educational attainment, and that upstream interventions addressing education access itself may be needed. The study is limited by its cross-sectional design (precluding causal inference), potential self-report bias, and lack of global thresholds for interpreting inequality magnitude. Further research comparing Kerala to national and global data is warranted.