Association Between Glycated Hemoglobin and Breast Cancer Among Women at a Referral Hospital in Meru County, Kenya
TL;DR
Glycemic status shows a strong association with breast cancer in this Kenyan population; prospective population-based studies are needed before HbA1c can be recommended as a breast cancer screening tool.
Abstract
The rising dual burden of breast cancer and type 2 diabetes mellitus (T2DM) in Sub-Saharan Africa warrants examining their overlap. This study examined the association between glycated hemoglobin (HbA1c) and breast cancer status at a hospital in Meru County, Kenya. An unmatched case-control study enrolled 285 women: 142 with histologically confirmed breast cancer diagnosis and 143 with benign breast masses. Chi-square, t-tests, ANOVA with Tukey HSD testing, logistic regression, and ROC analysis were used. HbA1c ≥6.5% was present in 84.5% of cases (120/142) versus 34.3% of controls (49/143; χ² = 74.515, df = 1, p < 0.001). Mean HbA1c was higher among cases (6.89% ± 0.75) than controls (5.82% ± 0.71; t (283) = 12.445, p < 0.001, mean difference 1.07, 95% CI: 0.90–1.24). In multivariable logistic regression, T2DM (adjusted OR = 5.619, 95% CI: 2.802–11.267), alcohol use (aOR = 4.041, 95% CI: 1.707–9.569), family history of breast cancer (aOR = 2.763, 95% CI: 1.340–5.587), hormonal contraceptive use (aOR = 2.151, 95% CI: 1.140–4.058), and BMI (aOR = 1.389 per unit, 95% CI: 1.268–1.521) were independently associated with case status; age was not (aOR = 1.000, 95% CI: 0.969–1.033). HbA1c ≥6.5% discriminated cases from controls with moderate accuracy (AUC = 0.751, 95% CI: 0.693–0.809; sensitivity 84.5%, specificity 65.7%). Mean HbA1c did not differ significantly across stages I–III (ANOVA, F(3,139) = 2.599, p = 0.055), although Stage IV cases (n = 8) recorded a higher mean (7.56%) than Stage II (6.78%; Tukey HSD, p = 0.031). Because T2DM status was derived from the HbA1c ≥6.5% threshold, and HbA1c was measured post-diagnosis, findings reflect association within this sample rather than validated screening performance. Glycemic status shows a strong association with breast cancer in this Kenyan population; prospective population-based studies are needed before HbA1c can be recommended as a breast cancer screening tool.