1 Document heading Hypercalcemia in patients with tuberculosis and HIV infections in Northwest Ethiopia Bemnet Amare 1* , Solomon Meseret 2 , Tomoki Yabutani 3 , Beyene Moges 4 , Afework Kassu 4 1 Department of Medical Biochemistry, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia. 2 Department of Biostatistics, School of Public Health, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia. 3 The Department of Chemical Engineering, University of Tokushima, Tokushima, Japan 4 Department of Microbiology, Immunology and Parasitology, College of Medicine and Health Sciences, University of Gondar, P.O. Box 196, Gondar, Ethiopia. Asian Pacific Journal of Tropical Disease (2012)1-6 Asian Pacific Journal of Tropical Disease journal homepage:www.elsevier.com/locate/apjtd *Corresponding author: Bemnet Amare, Department of Medical Biochemistry, University of Gondar, P.O. Box 196, Gondar, Ethiopia. Tel: +251 918 71 1800 Fax: +251 581 11 14 79 E-mail: amarebem6@gmail.com 1. Introduction Estimates by the World Health Organization indicate that there are more than 9 million new active cases of TB and close to 2 million deaths per year [1] , and that 2.6 million new cases of HIV infection and 1.8 million AIDS-related deaths occur per year [2] . Literatures show that TB is the largest single cause of death in the setting of AIDS, accounting for about 26% of AIDS-related deaths [3] Both TB and HIV have profound effects on the immune system, as they are capable of disarming the host ’ s immune responses through mechanisms that are not fully understood [4] . HIV coinfection is the most powerful known risk factor for progression of M. tuberculosis infection to active disease, increasing the risk of latent TB reactivation [3] . Likewise, TB has been reported to exacerbate HIV infection [5] . Multiple disturbances of electrolyte metabolism and endocrine regulation have been observed in patients infected with the HIV [6] . However, its effect on the development of hypercalcemia in patients with and without TB has not been established. Calcium is the most abundant mineral in the body and is used for strong bones and teeth. It is also required for muscle contraction, to transmit pulses throughout our nervous system, blood vessel expansion and contraction and the secretion of hormones and enzymes. The association between TB and hypercalcemia is well recognized [7-10] . The reported incidence of sever hypercalcemia in TB varies widely between countries, probably because of differences in the vitamin D and calcium intake, the amount of sun exposure, the extent of disease and the criteria for hypercalcemia [11-13] . Longitudinal studies from India [14] , in Malaysia [11] and the United States [9] reported ARTICLE INFO ABSTRACT Article history: Received 15 June 2012 Received in revised form 27 July 2012 Accepted 18 October 2012 Available online 28 October 2012 Keywords: Calcium Hypercalcemia Tuberculosis HIV Objective: To determine incidence of hypercalcemia among TB patients with and without HIV infection before and after anti-TB chemotherapy in tropical settings of Northwest Ethiopia. Method: Serum levels of calcium were determined using an inductively coupled plasma mass spectrometer from all subjects at baseline and from 60 TB patients (34 with HIV co-infection) at the end of an intensive phase of anti-TB chemotherapy. Results: At baseline, significant difference was found between the mean albumin-adjusted calcium levels in TB patients with HIV (11.95暲3.72) and controls (9.81暲1.59) (P=0.03). Hypercalcemia (serum calcium of > 10.5 mg/dL) was observed in 62.2% and 43.2% of TB patients with and without HIV co-infection, respectively. The serum levels of calcium did not significantly change after anti-TB chemotherapy both in patients with (n = 34) and without (n = 26) HIV co-infection. Conclusions: The present study suggests that TB itself appears not to be responsible for hypercalcemia; however, rates of hypercalcemia are high in TB and HIV co-infected patients in the tropical settings of Northwest Ethiopia, of rarely symptomatic. Anti-TB chemotherapy does not improve the incidence of hypercalcemia in both groups with HIV co-infection and without. Contents lists available at ScienceDirect