Growth and pubertal development in children with sickle cell anaemia at Muhimbili National Hospital 2010

Abstract

ABSTRACT Background: Sickle cell anaemia (SCA) is a genetic disorder with multisystem manifestations. Paediatricians and general practitioners dealing with these patients need to know the overview of the genetics, diagnosis, clinical manifestations, and treatment of sickle cell anaemia associated complications. Poor growth and delayed pubertal development is often impaired in children with SCA. Abnormalities include low Z-scores for height and weight for age, delay in skeletal and sexual maturation. Poor growth and lack of sexual development may lead to emotional and social difficulties and in some patients their consequences can persist to adulthood.The magnitudes of delayed puberty in children with SCA in Tanzania have not been studied; however there is a study which evaluated the growth and pubertal development parameters for the non sickle cell children in Dar es Salaam City. In Africa few studies on pubertal development have been published and hence, the need for baseline reference data to facilitate the interpretation of sexual maturity assessments in Tanzanian children with sickle cell anaemia. Objective: To compare growth and pubertal development of children with SCA to normative references of urban Tanzanian children in Dar es Salaam. Methodology: This was a hospital based cross-sectional study with historical control design. Anthropometric measurements of growth and Tanner stages of sexual development of children with sickle cell anaemia aged between 6 and 18 years were compared with normative references for growth and sexual maturity levels derived from a previous study of 3384 Dar es Salaam urban Tanzanian children aged 6-18 years. Data was analyzed using STATA IC version 9 statistical packages. In addition, z-scores were calculated based on UK population reference data which is probably currently the most comprehensive data set available for this age group. Results: During the study period, 301 children were recruited out of whom 144 (48%) were females .The mean age (SD) of the subjects was 12.4 (±3.5) years and the mean age by sex was not statistically significant (P=0.108). Girls with SCA were at puberty (breast Tanner stage 2) at a mean age (SD) of 14.8 (±4.6) years as compared to 11.5 (±1.5) years for non SCA controls and the difference was statistically significant (P<0.001). Boys with SCA were at puberty (genital Tanner stage 2) at a mean age of 13.2 (±2.3) years as compared to 12.3 (±1.5) years of the non SCA boys in Dar es Salaam urban population (P<0.001).The mean age (SD) at menarche vi for girls with SCA was 14.8 (±1.1) years and for the girls without SCA was (13.2 (±1.3) years (P<0.001). Children with SCA had low z-scores for height for age, weight for age and Body mass index than children without SCA (P<0.001). There was no statistically significant difference in weight, height, body mass index and waist circumference throughout puberty between girls with and without SCA (P>0.05 throughout). Boys with SCA had low mean weight (P=0.001), height (P=0.009), and body mass index (P<0.001) as compared to non SCA boys at puberty. Advanced sexual maturation was associated with more body fat by sex (P<0.001). In multivariable logistic regression analysis, body fat percent independently predicted puberty in girls but not in boys. Conclusion: Children with SCA have impaired growth, delayed puberty, and poor nutritional status.. Independently body fat percent predicted puberty in girls with SCA and advanced sexual maturation was associated with more body fat. Recommendations: The findings can be used as a baseline data in the interpretation of precocity or delayed puberty in children with sickle cell anaemia population. A longitudinal study is needed to determine exactly when one will be entering and leaving a Tanner stage also establishing the possible causes of disproportional growth between girls and boys with SCA during puberty.