Sahel Medical Journal

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 22  |  Issue : 2  |  Page : 64--70

Risk factors for chronic kidney disease among in-school adolescents in Ibadan, Southwest, Nigeria


Olufolake Onuche Abu1, Yemi Raheem Raji2, Olukemi Kehinde Amodu1,  
1 Institute of Child Health, College of Medicine, University of Ibadan, Ibadan, Oyo State, Nigeria
2 Department of Medicine, College of Medicine, University of Ibadan and University College Hospital, Ibadan, Oyo State, Nigeria

Correspondence Address:
Dr. Yemi Raheem Raji
Department of Medicine, College of Medicine, University of Ibadan and University College Hospital, Ibadan, Oyo State
Nigeria

Abstract

Background: Chronic kidney disease (CKD) a common noncommunicable diseases associated with high morbidity and mortality. Epidemiology of CKD in Sub-Saharan Africa suggests high burden of CKD with early onset. The adolescent age group has been reported to be at increased risk of kidney disease arising from prevalent risky behaviors and obesity. The in-school adolescents constitute a large group of at-risk individuals that are easily accessible for screening. Objective: This study aimed to determine the prevalence of kidney CKD and its risk factors among in-school adolescents. Materials and Methods: This was a cross-sectional study of 420 in-school adolescents in Ibadan, Southwest Local Government Area, Ibadan, Nigeria. A pretested questionnaire was administered to the participants selected using multistage clustered sampling technique. Anthropometric and blood pressure measurements were taken, urine samples were collected for dipstick urinalysis, while 80 participants provided blood for serum creatinine and estimated glomerular filtration rate (eGFR). Results: A total of 420 in-school adolescents participated in the study, the mean age was 14.0 ± 2.3 years and 57.4% were female. The mean body mass index, mid-upper arm circumference (MUAC), and median eGFR were 19.9 ± 3.7 kg/m2, 20.8 c ± 3.7 cm, 96.1 (36.6–156) ml/min/1.73 m2, respectively. The common risk factors for CKD were herbal consumption (59.2%), abnormal MUAC (47.1%), and truncal obesity (28.3%). Proteinuria, hematuria, and CKD were observed in 10%, 16%, and 21.3% of the participants, respectively. Excess body weight (odds ratio [OR], 5.03), abnormal MUAC (OR, 4.11), hypertension (OR, 2.51), and family history of kidney disease (OR, 1.58) were independently associated with CKD. Conclusions: CKD and its risk factors were common among in-school adolescents and the occurrence of CKD was associated with excess body weight, abnormal MUAC, hypertension, and family history of kidney disease.



How to cite this article:
Abu OO, Raji YR, Amodu OK. Risk factors for chronic kidney disease among in-school adolescents in Ibadan, Southwest, Nigeria.Sahel Med J 2019;22:64-70


How to cite this URL:
Abu OO, Raji YR, Amodu OK. Risk factors for chronic kidney disease among in-school adolescents in Ibadan, Southwest, Nigeria. Sahel Med J [serial online] 2019 [cited 2019 Sep 23 ];22:64-70
Available from: http://www.smjonline.org/text.asp?2019/22/2/64/260835


Full Text



 Introduction



Chronic kidney disease (CKD) is one of the common noncommunicable diseases (NCD) associated with high morbidity and mortality worldwide.[1],[2] CKD is defined as progressive and usually irreversible functional and structural abnormalities of the kidney, lasting 3 months or more irrespective of the glomerular filtration rate (GFR), or reduction in estimated GFR (eGFR) <60 ml/min/1.73 m2 for 3 months or more.[3] CKD is estimated to affect between 8% and 16% of the world population, while >2 million individuals are leaving with end-stage kidney disease (ESKD).[4] While the kidney disease-associated mortality rate is declining in high-income countries, the burden of CKD is increasing in low- and middle-income countries (LMICs).[5] This burden is not only limited to the adult population but also high among the children. Onochie et al.[6] observed that the prevalence of ESKD among children increased from 12.5 in the 1985 to 1990 periods to 15/million children after 1995 in Portharcourt, Nigeria. Similarly, Olowu et al.[7] reported estimated incidence of CKD of 11/million children population (pmcp)/year while prevalence averaged 48 pmcp/year.

Despite the high burden of CKD in children, most LMICs have no structured policy and strategies for early detection and treatment of CKD and its risk factors among children. Moreso that CKD tends to have early onset and increased severity among individuals of African descent.[8] Adolescents are particularly vulnerable to CKD and its risk factors, because at this stage, most are exposed to physical and psychosocial health issues and peers pressure for risky lifestyles.[9],[10],[11] Studies have shown that NCDs are on the rise among the adolescents, particularly in LMICs where there is increasing preference for adoption of Western lifestyle and diets.[12],[13] The in-school adolescents form a large cohort the population at risk of CKD and other NCDs, thus appropriate policy for regular screening at school will be a cost-effective strategy toward early identification and treatment of CKD and its risk factors. This study aimed to determine the prevalence and risk factors for CKD among in-school adolescents.

 Materials and Methods



This is a cross-sectional survey of 420 in-school adolescents in the Southwest Local Government Area of Oyo state, Nigeria. Ethical approval was obtained, from the Oyo State ethics board, under the Division of Research and Statistics, Department of Planning, Oyo State Ministry of Health, with the approval number AD/13/479/908. The approval was obtained on March 2, 2015. Approvals were also obtained from the local school board and the participating school heads. Informed consents were obtained from all the participant parents/guardians while assent was also obtained from all participants. A multistage clustered sampling approach was used to select the participants. A systematic and random sampling using a table of random numbers were adopted in selecting 5 schools (2 private and 3 public) from all the 77 schools (29 government owned and 48 privately owned) in Ibadan, Southwest LGA. Eighty participants were selected randomly from the first four schools and 100 participants from the 5th school. In each of the school and 20 students were randomly selected from each of the four randomly selected classes, while 5 classes were selected in the fifth class using the class student registers. Inclusion criteria were in-school adolescents age 10–19 years who gave assent and consent obtained from parent. Excluded were individuals with age <10 years or >19 years, had an ongoing febrile illness, ongoing menstruation, history of malignancy, history of urinary tract infection, and those who declined assent or parents declined consent. Interviewer's administered questionnaire was administered on all participants and information obtained were sociodemographic characteristics, lifestyle, dietary habits, meal pattern, physical activity, risk factors for kidney disease, awareness of kidney diseases and its risk factors, medical and surgical history, and family history of kidney disease. Physical examinations carried out in the participants include anthropometric measurements (weight, height, and mid-upper arm circumference [MUAC]), blood pressure, and pulse rate. About 10 ml of urine was obtained from each participant and 10-point urinalysis was carried out on all specimens. Only 80 participants assented and parents gave consents for blood collection, and in those participants, 10 ml of venous blood was obtained for serum creatinine estimation. The eGFR was calculated using Schwartz' equation.[14]

Definition of terms

Hypertension was defined as previous diagnosis of hypertension by a physician or on antihypertensive medications or had an average systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) that is ≥95th percentile for sex, age, and height on three or more occasions, while prehypertension was defined as SBP and/or DBP ≥90th percentile for sex, age, and height.[15] Diabetes mellitus (DM) was defined as previous diagnosis of DM by a physician or being on antidiabetic medications or fasting plasma glucose >7.1 mMol/L or 2-h postprandial plasma glucose greater 11.1 mMol/L at least once with symptoms of DM or on 2 or more occasions without symptoms.[16] Hyperglycemia was defined as random plasma glucose >11.1 mMol/L. Overweight and obesity were defined as body mass index (BMI) of between 85 and 95th and >95th percentile for the age and sex, respectively, while truncal obesity was defined as having both age- and gender-specific waist circumference percentile ≥90th and/or waist–hip ratio (WHR) ≥0.5.[17],[18] Abnormal MUAC was defined as MUAC >22 cm in female and >23 cm in male.[19] CKD was defined as the presence of at least 1+ proteinuria and/or eGFR <60 ml/ml/1.73 ml/min/1.73 m2.[3],[20]

Statistical analysis

The data were analyzed using Statistical Package for the Social Sciences (SPSS) version 20 (IBM Corporation, released 2011., IBM SPSS Statistics for Windows, Version 20.0. IBM Corp., Armonk, NY, USA). Continuous variables were expressed as mean with standard deviation while categorical variables were expressed as proportions or percentages. The association between continuous variables; age, blood pressure, eGFR, and BMI were determined using Student's t-test while association between categorical variables and impaired kidney function were determined using Chi-square test. Multiple logistic regression analyses were used to determine factors associated with CKD. All variables were considered statistically significant if the P < 0.05.

 Results



A total of 420 in-school adolescents took part in the study. The mean age of the participants was 14.0 ± 2.3 years, majority (72.1%) were 13 years and above while 241 (57.4%) were female. The mean BMI, MUAC, and WHR were 19.9 ± 3.7 kg/m2, 20.8 ± 3.7 cm, and 0.9 ± 0.4, respectively, while the mean DBP, SBP, and Random Plasma Glucose (RPG) were 67.1 ± 10.5 mmHg, 104.8 ± 14.5 mmHg, and 5.5 ± 1.3 mmol/L, respectively [Table 1]. The median serum creatinine and mean eGFR were 78.8 ± 31.6 μmol/L and 96.1 (36.6–156) ml/min/1.73 m2, respectively [Table 1]. Majority of the in-school adolescents were of Yoruba Ethnic tribe, while 169 (40.2%) attended privately owned primary schools and 251 (59.8%) were in government-owned schools, [Table 1].{Table 1}

The common risk factors for CKD identified among the participants were herbal consumption, abnormal MUAC, truncal obesity, exposure to heavy metals, and being overweight, [Table 2]. Features of kidney disease identified among the 420 participants were proteinuria 42 (10.0%) and hematuria 67 (16.0%) while reduced eGFR was 5 (6.3%) and CKD defined as reduced eGFR and/or proteinuria was 17 (21.3%) among the 80 participants that provided blood sample, [Table 3]. On bivariate analysis, factors associated with CKD were family history of kidney disease, prehypertension, hypertension, excess weight, and abnormal MUAC, [Table 4], while only hypertension, excess weight, abnormal MUAC, and family history of kidney disease were independently associated with CKD on multivariate analysis, [Table 5].{Table 2}{Table 3}{Table 4}{Table 5}

 Discussion



Our study identified common risk factors for CKD among in-school adolescents and these factors include prehypertension, hypertension, overweight, obesity, truncal obesity, abnormal MUAC, family history of kidney disease, exposure to heavy metals, and consumption of herbal medications. Hypertension was observed in 6.9% of the participants, this was similar to 4.6% reported by Ejike et al.[21] among adolescents in Lokoja and Ajaokuta, Kogi state, Nigeria and 4.3% observed by Mijinyawa et al.[22] among similar group in Kano, Nigeria. The slight increase in hypertension prevalence in our study may suggest a trend in rise in the prevalence of hypertension among adolescents in Nigeria. Surprisingly, none of the participants with hypertension in our study was diagnosed with hypertension before their enrolment in the study, suggesting that hypertension awareness is low in this subpopulation. Hypertension in this in-school adolescent population are likely to be secondary, though our study did not set out to determine the causes of hypertension among the participants, it is possible that the occurrence of hypertension may be a manifestation of an underlying kidney disease. The prevalence of prehypertension in this study was 8.8%, this was at variance with 22% reported in similar population by Ejike et al.,[21] the disparity in the prevalence compared to our study could be explained by the inclusion of adults 18–20 years in their study. The indices of excess weight were prevalent among the participants, the prevalence of overweight and obesity of 15.7% and 3.3% in our study were comparable to 17.3% and 5.4%, respectively, reported by Akinpelu et al.[23] among adolescents in Lagos. Abnormal MUAC and truncal obesity were also prevalent among the in-school adolescents, and these are manifestations of obesity epidemic among adolescents. Our findings support the previous report of rising burdens of childhood obesity in Nigeria, especially with increasing adoption of Western diets and long hours spend behind computer and other electronic games by the children. More than half of the participants consumed herbal preparations, and this agrees with the previously reported widespread herbal use in Nigeria, perhaps the widespread of unregulated herbal preparations may yet be the undefined major contributor of CKD burden among young Nigerians.[24],[25],[26] The high prevalence of risk factors for CKD among the in-school adolescents may have a correlation with early onset of ESKD in Nigeria.

Features of kidney disease identified in the participants include proteinuria, hematuria, and reduced eGFR. Proteinuria prevalence of 10% reported in our study is higher compared to 5.3% and 3.6% reported by Oviasu and Oviasu[27] and Akor et al.,[28] respectively, the observed disparity may suggest changing trend in the epidemiology of kidney disease in Nigeria, as their studies were conducted >10 years ago. The prevalence of proteinuria in our study was lower compared to 33.2% reported by Okpere et al.[29] The difference could be explained by variation in the definition of proteinuria; Okpere et al.[29] used Micral urinary stick and microalbuminuria >20 mg/g was defined as proteinuria unlike our study that defined proteinuria as dipstick proteinuria of one plus or greater. Albuminuria is a more sensitive marker of kidney disease than dipstick proteinuria,[30] it is however more expensive and not readily available in most rural communities in Nigeria. Our study observed hematuria in 16% of the participants, this was higher than 1.5% and 4.7% reported by Akor et al.[28] and Oviasu and Oviasu,[27] the high prevalence of hematuria in our study may have been due to overdiagnosis as only one spot urine sample was tested, transient causes of hematuria may have added to the overdiagnosis. CKD was observed in 21.3% of the 80 participants that agreed to blood sample collection, this agrees with high prevalence of CKD in Nigeria as earlier reported by Olowu et al.[7] who observed the overall mean incidence of CKD of 11 pmcp/year and prevalence averaged 48 pmcp adolescent Nigerians. Our prevalence was also similar to the finding by Oluyombo et al.[31] who reported a CKD prevalence of 19.9% among adult Nigerian population. These findings suggest that CKD in the in-school adolescents may be contributing to the high burden of CKD and ESKD in Nigeria, particularly the early onset disease.

Hypertension, excess weight, abnormal MUAC, and family history of kidney disease were factors independently associated with the development of CKD among the in-school adolescents. These factors except for the family history of kidney disease were modifiable, and lifestyle modifications such as low salt diets, avoidance of high-calorie foods, and regular exercise both at home and in school should be part of the preventive strategies, to reduce the burden of kidney disease in this group. Regular in-school screening for kidney disease and risk factors and health education to the students, teachers, and parents will be potentially rewarding measures geared towards preventing the development of CKD and its risk factors. Finally, the departments/ministries of health and education at the local, state, and federal levels should work together to setup policy framework for the reintroduction of effective school health services, as this will go a long way in early detection and prompt treatment of CKD and its risk factors. This study is not without limitations and these include the fact that dipstick proteinuria, hematuria, and eGFR were only measured once, therefore, increasing the likelihood of overdiagnosis of kidney disease and its features. Second, only 80 of the participants agreed to blood collection, and analysis of CKD prevalence was based on this subgroup.

 Conclusions



This study has highlighted that CKD and its risk factors are common among in-school adolescents in Nigeria. Hypertension, excess weight, abnormal MUAC, and family history of kidney disease were factors independently associated with CKD in the in-school adolescents. Health education, regular in-school screening, and reintroduction of functional school health services are measures that should be incorporated into the preventive health policies for the adolescent population in the country.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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