Evaluation of Bilirubin Estimates in Newborns From Smartphone Digital Images in a Population in Botswana
Phase: NA
Conditions: Neonatal Jaundice, Neonatal Hyperbilirubinemia
Sponsor: Hillerod Hospital, Denmark

Date of document: March 1, 2023 
 
1 
 
 
 
 
Evaluation of bilirubin estimates in 
newborns from smartphone digital images 
in a population in Botswana 
 
 
 
 
 
 
 

Date of document: March 1, 2023 
 
2 
Table of contents 
1. 
Introduction ..................................................................................................................................... 3 
1.1. 
Background ........................................................................................................................................... 3 
1.2. 
Problem statement ................................................................................................................................ 6 
1.3. 
Purpose of study ................................................................................................................................... 7 
1.4. 
General Objective ................................................................................................................................. 7 
1.5. 
Specific Objectives ................................................................................................................................ 7 
1.6. 
Scope of study ....................................................................................................................................... 7 
1.7. 
Justification .......................................................................................................................................... 8 
1.8. 
Significance of study ............................................................................................................................ 8 
2. 
Methodology ..................................................................................................................................... 9 
2.1. 
Study design .......................................................................................................................................... 9 
2.2. 
Study setting .......................................................................................................................................... 9 
2.3. 
Study population and sample size calculations ................................................................................. 10 
2.5. 
Selection criteria ................................................................................................................................. 11 
2.6. 
Data collection .................................................................................................................................... 12 
2.7. 
Data analysis ....................................................................................................................................... 14 
2.7.1. 
Laboratory analysis ............................................................................................................................ 14 
2.7.2. 
Statistical analysis .............................................................................................................................. 14 
2.8. 
Risk assessment .................................................................................................................................. 14 
2.9. 
Research team ..................................................................................................................................... 15 
2.10. 
Ethical consideration .......................................................................................................................... 16 
2.11. 
Limitations and mitigation ................................................................................................................. 17 
2.12. 
Plan for validation and dissemination ............................................................................................... 17 
Sources .................................................................................................................................................... 18 
Appendices .............................................................................................................................................. 24 
 
 
 
 

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1. Introduction  
 
1.1. Background 
 
Neonatal jaundice is a condition in newborns with elevated levels of the waste product bilirubin, 
also known as hyperbilirubinemia. It is primarily caused by a combination of the rapid turnover 
of red blood cells and the immature liver functions in the newborn. Neonatal jaundice affects 
approximately 60 to 80 % of newborns but is usually self-limiting and harmless. The condition 
is still potentially dangerous because bilirubin can accumulate in the basal ganglia of the brain, 
where it can cause permanent brain damage. Such brain damage, better known as kernicterus, 
can manifest as cerebral palsy, deafness, language difficulty, or in the worst cases, be fatal. 1 
 
Bhutani et al. estimated the incidence and impairment of neonatal jaundice for 2010 and 
concluded that failure to manage hyperbilirubinemia results in 114 100 avoidable neonatal 
deaths and many newborns who grow up with severe disabilities. 2 Three-quarters of these 
deaths are estimated to occur in the poorest regions of the world; sub-Saharan Africa and South 
Asia. Neonatal jaundice is one of the top three leading causes of death among newborns in sub-
Saharan Africa. 1 
 
The main challenge in reducing the burden of neonatal jaundice is to identify children at risk at 
an early stage so that effective treatment can be given at an early stage. 3 Treatment of 
hyperbilirubinemia is usually done by phototherapy and, in some extreme cases, by blood 
transfusion. In some areas, sunlight is an optional treatment. 4 
 
Standard detection of neonatal jaundice varies in different countries. In Denmark, all infants 
are screened by transcutaneous bilirubinometers (TcB). The limit for when to measure total 
serum bilirubin (TSB) based on cutaneous bilirubin depends on the TSB standardization and 
which type of cutaneous bilirubinometer is used (BiliCheck/Minolta) in the individual 
department. 5,6 In African countries, however, detection of neonatal jaundice usually includes a 
clinical risk evaluation by visual assessment (VA) and sometimes a diagnostic blood sample to 
measure the level of total serum bilirubin (TSB). 
 

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In cases of high bilirubin levels, most countries apply subsequent capillary/venous samples for 
follow-up and to determine the need for therapy. Invasive blood sampling is linked to stress, 
pain, and substantial blood loss. Moreover, there is an increased risk of infections.  
 
VA of neonatal jaundice is often based on the cephalocaudal progression of the yellowness 
using Kramer’s scale, which assumes that a higher number corresponds to an increased level of 
serum bilirubin7 (Figure 1). This is the first-step screening option where other types of 
equipment are lacking. 8 Several studies have shown that VA is not a sufficient indicator on its 
own and unreliable as a screening tool for further testing. 9-13 
 
 
Fig. 1 Kramer’s scale 
 
To reduce the need to draw blood from the newborn, non-invasive devices that measure 
bilirubin concentration by shining light through the skin, such as transcutaneous 
bilirubinometers (TcB), have been developed. 14 TcB is one of the methods recommended by 
the American Academy of Pediatrics for the assessment of the risk of hyperbilirubinemia of 
newborns before discharge. 15 It is a safe, non-invasive method, and some studies have shown 
that its use can reduce the number of blood draws by 38,5%. 16 TcB shows a good correlation 
with blood samples, also in different ethnicities. 17 However, this is only true for the BiliCheck 
bilirubinometer. The Minolta bilirubinometer shows a higher transcutaneous bilirubin 
estimation in dark-skinned infants than in light-skinned infants. Additionally, it underestimates 
transcutaneous bilirubin when higher TSB levels are present. 5  

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Lab equipment for TSB measurements and TcB devices is expensive, with a price range from 
6.000 to 10.000 US dollars, thus making them practically unavailable in low-income countries. 
Because most deaths due to neonatal jaundice occur in low-income countries, there is a 
significant unmet need for simple, reliable, and affordable technologies to identify at-risk 
newborns. Mobile health, or mHealth, is an area with increased focus, as cell phone technology 
and smartphones are found worldwide, also in regions with scarce resources. This has given 
hope for new affordable solutions for global health. 18 
 
Picterus AS is a private limited liability company founded in Trondheim, Norway. They have 
developed a new smartphone app, Picterus Jaundice Pro (Picterus JP), that combines previous 
research on the bio-optics of jaundice in newborn skin with a mHealth approach. 19 Picterus JP 
uses an algorithm based on color analysis of a digital image to estimate the bilirubin levels in 
the blood, together with a unique color calibration card to adjust for different light conditions 
and the automatic adjustments in the phone (figure 2).  
 
 
 
Fig. 2 Workflow of Picterus JP system. A) A photo of the newborn is taken, B) colors from the calibration card 
are used to calibrate the image, C) calibrated colors are compared with an extensive database of color- and 
bilirubin pairs, and D) the matching bilirubin estimate is presented to the user. 
 
Picterus JP has been tested in 350 Caucasian and 170 Latin-American newborns, with mainly 
parents’ skin types 1 to 4 according to the Fitzpatrick scale (Figure 3) and skin color 1 to 3 
according to Neomar’s neonatal skin color scale (Figure 4). 20,21 The studies showed a Pearson 
correlation index of 0.83 to 0.88 and sensitivity of 90 to 100% to detect newborns with severe 
jaundice, defined as TSB above 250 μmol/L and specificity of 70 to 80%. 
 

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6 
However, there is still uncertainty about how Picterus JP works in newborns with high melanin 
content (Asian and African population / Neomar’s scale 4). Melanin could potentially influence 
the results, as it is one of the essential absorbers of light in the skin. However, melanocytes are 
immature at birth, and melanin levels in the skin are lower in newborns compared to adults. 22 
 
   
Fig. 3 Fitzpatrick scale 
 
  
 
Fig. 4 Neomar’s skin color scale for newborns 21 
 
 
 
1.2. Problem statement 
 
Picterus performed a pilot study in Uganda from December 2019 to March 2020, which 
included 167 newborns. Results showed a Pearson correlation index of 0.59 between TSB and 
the Picterus image estimate, a sensitivity of 66%, and a specificity of 94%, when the cut-off 
was set to 250 µmol/L. Only six newborns had bilirubin levels higher than 250 μmol/L. It was 
concluded that more data is needed to optimize the performance of the tool for dark skin, 
including spectrophotometric measurements of skin color reflectance and newborns with higher 
bilirubin levels.  

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7 
Currently, there is a running project in Uganda where data is collected from newborns with a 
broader range of bilirubin levels and high melanin content. Additional measurements of skin 
color reflectance with a spectrophotometer are made to adjust the Picterus JP algorithm and 
optimize the app performance. However, more data is needed to determine the adequacy of the 
app. Therefore, collecting data from different populations, such as in Botswana, will be 
valuable.  
 
1.3. Purpose of study 
 
This study will be conducted at a hospital in Botswana, where we aim to collect data from 
newborns with a broader range of bilirubin levels and high melanin content in a different 
population than in the Uganda study.  
 
1.4. General Objective 
 
The general objective is to investigate the use of Picterus JP in a population with high melanin 
content in the skin. 
 
1.5. Specific Objectives 
 
The specific objectives of this study are: 
 
i. 
To assess the correlation between estimations of bilirubin obtained by Picterus JP 
with TSB, and TcB, in newborns with high melanin content in the skin. 
ii. 
To determine the accuracy of Picterus JP used as a screening tool to identify high 
levels of bilirubin in newborns with melanin content in the skin.  
 
1.6. Scope of study  
 
The study will be conducted in the neonatal unit (NNU) and the postnatal ward (4G) at 
Princess Marina Hospital in Gaborone, the capital of Botswana. 
 
 

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1.7. Justification 
 
We hypothesize that the Picterus JP will offer bilirubin level estimates that are highly correlated 
to bilirubin levels measured in blood samples in a population in Botswana. Following our 
hypothesis, the short-term goal for this project is to demonstrate that this screening method can 
be used to identify children with severe neonatal jaundice independent of skin color. Thus, 
providing a cheaper, patient-friendly, and more readily available means of neonatal jaundice 
detection.  
 
1.8. Significance of study  
 
The long-term goal is that with the implementation of the app, the identification of newborns 
with jaundice will be improved and, thus, referred at an earlier stage for diagnostics and 
treatment. This would lead to reduced neonatal morbidity, mortality, and fewer children with 
permanent disabilities following hyperbilirubinemia, also in patients with high melanin content, 
such as the population in Botswana. The clinicians at Princess Marina Hospital will benefit 
from this as they will be equipped with a cheap, readily available application for detecting 
neonatal jaundice. 
 
 
 

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2. Methodology 
 
2.1. Study design 
 
The study will be a diagnostic accuracy cross-sectional study with quantitative methods of 
data collection. 
 
2.2. Study setting 
 
The study will be conducted in the neonatal unit (NNU) and the postnatal ward (4G) at the 
Princess Marina Hospital (PMH) in Gaborone, Botswana. PMH is a provincial, government-
funded hospital and the largest referral hospital in Botswana.  
 
The hospital offers preventive, curative, and rehabilitation services and serves as a primary, 
district, and tertiary hospital. The hospital has an in-patient capacity of more than 500 beds and 
handles a minimum of 2500 outpatients daily.  
 
The NNU has 38 beds distributed in 5 cubicles, is often overcrowded, and receives neonates 
from the on-site labor ward and babies referred from the surrounding clinics and district 
hospitals. On estimations from prof. Britt Nakstad, who is employed at the department, there 
are approximately 100 neonatal admissions per month (ranging from 82-127 monthly in 2017-
2022), including patients who need intensive care on ventilators. Of these are 47% girls and 
53% boys. The total mortality is 18% of the admitted infants. The estimated gestational age and 
weight of the patients at the NNU can be found in Table 2 and Table 3, respectively, and are 
based on the admitted infants in May 2022. In the postnatal ward, there are approximately 500 
mothers admitted monthly (ranging from 498-508 monthly in May-July 2022), including 
normal and c-section deliveries. 23 
 
 

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Gestational age 
n 
% 
< 28 weeks 
13 
14.1 
28-29 weeks 
8 
8.7 
30-31 weeks 
8 
8.7 
32-34 weeks 
14 
15.2 
35-36 weeks 
14 
15.2 
37-40 weeks 
29 
31.5 
> 40 weeks 
6 
6.5 
Total 
92 
100 
  
Table 2: Estimated gestational age at NNU 
 
 
Table 3: Estimated weight at NNU 
 
2.3. Study population and sample size calculations 
 
The study population will comprise 150 newborns from the Neonatal Unit and the postnatal 
ward at Princess Marina Hospital, a number determined by a sample size calculation based on 
standard errors of the 95% limit agreement, as described by Bland and Alman. 19  
The standard error of the 95% limit of agreement is given by 
, where s is the standard 
deviation of the differences between measurements by the two methods, and n is the sample 
size.  
 
The study performed at St. Olav Hospital showed a standard deviation (s) of the difference 
between bilirubin estimates from digital images to blood samples of 35 μmol/L. 20 A sample 
size (n) of 150 participants will then give the confidence interval of the limits of 9,8 μmol/L, a 
relevant size for clinical use.  
 
The study objective of this study is two-folded. First, we wish to determine the correlation 
between TSB measurement and Picterus image estimate of serum-bilirubin. Second, we wish 
to determine the accuracy of the Picterus App used as a screening tool.  
 
Weight 
% 
<1000 g 
10 
1000-1500 g 
20 
1500-2500 g 
25 
2500-4000 g 
40 
> 4000 g 
5 
Total 
100 

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The study conducted by Aune et al. found an AUC of 0.925. To calculate the sample size for 
this study we used the used the EasyROC tool, by setting an AUC of 0.9, a significance level 
of 0.5 and a power to 0.8. This gave the suggested sample size of 12 infants. In order to get a 
sufficient result for all bilirubin levels, we decided to apply our pilot data to see how many 
subjects were needed to receive a sample of 12 in three different groups; <100 µmol/L, 100-
200 µmol/L and >200 µmol/L. Through this calculation we came to the number of 115 infants.  
 
2.4. Participants and sampling procedure 
 
Participants will be recruited from the NNU and postnatal ward at the Princess Marina Hospital. 
The parents of newborns with and without signs of jaundice will be asked to participate.  
 
2.5. Selection criteria 
 
150 newborns will be included in this study. Participants will be recruited from the NNU and 
the postnatal ward.  
 
2.5.1. Inclusion criteria 
 
• Gestational age  
> 37 weeks 
• Birth weight   
> 2000 g and < 4500 g 
• Age   
 
> 24 hours and < 14 days 
• Infants requiring a blood sample for clinically suspected jaundice or other screening 
 
2.5.2. Exclusion criteria 
 
• Infants transferred to the pediatric ward for advanced treatment 
• Infants with a skin rash or other disease that affects the skin where measurements are 
performed 
• Infants that receive or have received phototherapy in the last 24 hours 
• Infants with an inborn disease 
 

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Newborns that have received phototherapy are excluded, as phototherapy will influence the 
result of transcutaneous measurements. 
 
2.6. Data collection 
 
Following informed consent, background data such as birth weight, age on examination, 
gestational age, and type of feeding will be obtained. Gestational age will be based on 
ultrasound determination and the last normal menstruation period (LNMP). The skin type of 
the infant will be classified according to the newborn Neomar’s scale score (Figure 4).  
 
Transcutaneous bilirubin estimates will be performed over the sternum of the infant. A Dräger 
Jaundice Meter JM-105 will be used in this study.  
 
Skin reflectance will be done using a CE-marked portable Konica Minolta spectrophotometer 
CM-700d. The spectrophotometer readings will be used to adjust the existing algorithm from 
Picterus to African skin and thereafter bilirubin estimates from the taken images will be 
determined.   
 
The Picterus calibration card will be fixed in place with a disposable back sticker on the 
newborn’s chest with the hole of the card placed over the infant’s sternum. A validated 
smartphone with Picterus JP will then be used to collect digital images, as shown below. Once 
the phone is aligned with the card, two sets of 6 images of each newborn will be captured, 3 
with flash and 3 without flash. After all the images are obtained, a unique ID will be displayed 
on the smartphone. This ID will be recorded on the case report forms and later used to pair 
clinical data and digital images.  
 
 
 
Fig.5 Picterus JP image procedure 
 

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A blood sample to determine TSB will be obtained within 60 minutes of obtaining the images 
and processed at the Department of clinical biochemistry in the hospital laboratory. In addition, 
TSB will be measured with neonatal bilirubin analyzer Neo-Bil Plus from DAS to assess the 
quality of the equipment. For the hospital laboratory analysis, 1 ml of blood is required and will 
be obtained either by venous puncture or heel prick. An additional 10 μl volume of blood will 
be collected in a heparinized capillary tube for analysis in the Neo-Bil Plus equipment.  
 
 

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2.7. Data analysis 
 
2.7.1. Laboratory analysis 
 
Total bilirubin levels will be measured at the Department of clinical biochemistry. 1 ml of blood 
is required for the analysis and can be obtained through venous blood sampling. This will be 
carried out by the collaborators in the neonatal unit. The analysis is performed on CC- Beckman 
Coulter AU 680 Analyzer 01. Laboratory equipment is calibrated and maintained according to 
standard procedures.  
 
2.7.2. Statistical analysis 
 
The bilirubin estimates from the images taken will be determined. The images will be compared 
to the TSB, NeoBil and TcB measurements using the Pearson correlation coefficient. Sub-
analysis for the different skin colors, gestational ages, days of life, and bilirubin levels will be 
performed for the TSB and image estimate. Sensitivity and specificity analysis will be 
calculated for different cut-off values using the ROC analysis. Systematic over- or under-
estimation of bilirubin levels will be evaluated using Bland-Altman plots. To avoid bias, the 
developer of the product – Picterus AS – will not be involved in statistical work-up or even see 
the raw data. 
 
2.7.3. Data handling 
 
Only anonymized data will be used in this research project. Images are cropped, so it is 
impossible to identify the newborn from the images. Data will be stored on secure, password-
protected computers, to which only leading investigators have access. ID key will be held at a 
safe location in Botswana and will not be transported from this location. Image analysis and 
statistical analysis will be performed in Denmark with the local principal investigator. Transfer 
from Botswana to Denmark will be performed following the rules at Princess Marina Hospital.  
 
2.8. Risk assessment 
 
The overall assessment of risk in this study is considered low.  

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The procedure of obtaining the smartphone images involves no risk of importance. Blood 
samples will be obtained by the standard method, and no additional risk is involved in this 
study.  
All bilirubin estimates from the digital images will be performed after collecting data, as the 
smartphone application has not yet been validated for this population. This leaves no risk of 
presenting false bilirubin estimates to participants.  
 
2.9.Research team 
 
The principal investigator, Julie Zimmer, is a medical student in her fourth year at the 
University of Copenhagen in Denmark. She is responsible for the management of the study and 
will provide training for the personnel in order to start up the project in Botswana. 
 
Co-investigator prof. Britt Nakstad (MD, Ph.D., MSc), is a medical doctor and neonatologist 
educated from the University of Oslo. In Botswana, she works as a neonatologist at the Princess 
Marina Hospital in Gaborone and as a professor at the University of Botswana. She will be 
inviting and enrolling patients in the study and collecting data. 
 
Co-investigator dr. Lizzy M Pezwa is soon to be a resident in pediatrics at the University in 
Botswana and will be inviting and enrolling patients in the study and collecting data. 
 
Co-investigator dr. Mammule Tau is a first-year resident that will be inviting and enrolling 
patients in the study and collecting data. 
 
Co-investigator prof. Bo Mølholm Hansen (MD, Ph.D.) is a medical doctor educated at the 
University of Copenhagen and works as a neonatologist at Hillerød hospital in Denmark. He 
will supervise the principal investigator in the planning process, statistical analysis, and the 
writing of the final article.  
 
Co-investigator dr. Anders Aune (MD) is a medical doctor educated at NTNU and works as a 
pediatrician at the Neonatal Intensive Care Unit at St. Olav Hospital. He holds a master’s degree 
in Public Health from Yale University. He has a strong passion for this project, as it follows an 
idea of him dating back to 2011. He will represent the Picterus team in this study, which will 
provide the project with the Picterus JP equipment and Neo-bil Plus bilirubin analyzer.  

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2.10. Ethical consideration 
 
Ethical clearance will be obtained from the National Committee on Health Research Ethics in 
Denmark, the Research Ethics Committee at Princess Marina Hospital, the Research Ethics 
Committee at the University of Botswana, and the Botswana Ministry of Health and Welfare.  
 
No harm will be done to the subjects in this study. Verbal and written consent will be obtained 
from the parents of each study participant in English or Setswana if necessary. If the mother 
cannot read or write, they will be excluded from the study. Data collected will be handled with 
confidentiality, and the names of subjects will be coded.  
 
The overall assessment of risk in this study is considered low. Obtaining the smartphone images 
involves no risk of importance, and the smartphone used will be disinfected between each baby. 
Blood samples will be obtained by the standard procedure, and no additional risk is involved in 
this study. For all studies with the goal of increasing the identification of disease, it is essential 
that treatment is available and that identified cases do not result untreated. In our study, the 
treatment consists of phototherapy, which is available at Princess Marina Hospital.  
 
The benefit for the participants in this study will be that they will receive the results of the 
jaundice examination. Furthermore, if this reveals that treatment for jaundice is necessary, the 
costs related to this treatment will be covered by the project.  
 
The ethical aspect of the potential unbalances between educated health professionals asking 
new parents, some with low education or illiterate, living in rural areas and not exposed to 
studies frequently. Asking them to accept that their children can participate in a study requires 
tact and concern. The parents must understand that participating is voluntary and that they can 
refuse with no negative consequences for their child’s care. Furthermore, they must be 
competent to make informed consent.  
 
 

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2.11. Limitations and mitigation  
 
mHealth applications is a relatively new field with an increasing number of applications being 
launched. A concern regarding mHealth applications targeted toward the general public has 
been that many applications are unreliable and may lead to false results. 24 Many medical-
related applications are developed entirely by non-medical people and made available without 
regulation or certification procedures. Picterus JP has been designed to fulfill all necessary 
criteria according to relevant ISO standards.  
 
2.12. Plan for validation and dissemination 
 
The results from this study will have relevance for the potential validation of the innovation. 
Studies demonstrating the tool’s potential in a high-burden setting will be necessary for users 
of the device. This is the first validation study following the study in Uganda. The results of 
this study will result in a published paper in a peer-reviewed journal. Further, we will try to 
communicate the study’s results through popular media and seminars in both countries.  
 
 

Date of document: March 1, 2023 
 
18
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(https://www.facebook.com/sepatela/posts/pfbid0RuWiu9Kf3Nfop23kKCjDbtqvVtH
wa3cajsE6nxeDGmUzSubjwbj6yostZHXFhpyNl). 
24. Boulos MN, Brewer AC, Karimkhani C, Buller DB, Dellavalle RP. Mobile medical 
and health apps: state of the art, concerns, regulatory control and certification. Online 
J Public Health Inform 2014;5(3):229. DOI: 10.5210/ojphi.v5i3.4814. 
25. Lilian de Greef MG, Min Joon Seo, Eric C Larson, James W. Stout, James A. Taylor, 
Shwetak N. Patel. Bilicam: using mobile phones to monitor newborn jaundice.  2014 
(https://dl.acm.org/doi/abs/10.1145/2632048.2632076 
https://ubicomp.org/ubicomp2014/proceedings/ubicomp_adjunct/posters/p39-
de%20greef.pdf). 
26. Leung TS, Kapur K, Guilliam A, et al. Screening neonatal jaundice based on the sclera 
color of the eye using digital photography. Biomed Opt Express 2015;6(11):4529-38. 
DOI: 10.1364/BOE.6.004529. 

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27. Taylor JA, Stout JW, de Greef L, et al. Use of a Smartphone App to Assess Neonatal 
Jaundice. Pediatrics 2017;140(3). DOI: 10.1542/peds.2017-0312. 
28. Aydin M, Hardalac F, Ural B, Karap S. Neonatal Jaundice Detection System. J Med 
Syst 2016;40(7):166. DOI: 10.1007/s10916-016-0523-4. 
29. Xiaoyue Dong XS, Zhangbin Yu, Shuping Han. Image-Based Neonatal 
Hyperbilirubinemia Screening after Hospital Discharge. Tehran University of Medical 
Sciences 2020. DOI:  https://doi.org/10.18502/ijph.v49i6.3359. 
30. Rong ZH, Luo F, Ma LY, et al. [Evaluation of an automatic image-based screening 
technique for neonatal hyperbilirubinemia]. Zhonghua Er Ke Za Zhi 2016;54(8):597-
600. DOI: 10.3760/cma.j.issn.0578-1310.2016.08.008. 
31. ZHAO BYDHXGMSMLHLYRCSD. [Neonatal and early infantile jaundice: 
assessment by the use of the smarphone]. Chin J Neonatol 2018 
(http://zhxsekzz.yiigle.com/CN101451201804/1049735.htm?utm_source=TrendMD&
utm_medium=cpc&utm_campaign=Chinese_Journal_of_Neonatology_TrendMD_0). 
32. Srujana Swarna SP, Balaji Chinnasami, Nirmala Manasa D., Balaji Ramraj. The smart 
phone study: assessing the reliability and accuracy of neonatal jaundice measurement 
using smart phone application. International Journal of Contemporary Pediatrics 2018. 
DOI: http://dx.doi.org/10.18203/2349-3291.ijcp20175928. 
33. Moyer VA, Ahn C, Sneed S. Accuracy of clinical judgment in neonatal jaundice. Arch 
Pediatr Adolesc Med 2000;154(4):391-4. DOI: 10.1001/archpedi.154.4.391. 
34. Sara M. Acosta-Torres MTT-E, José A. Colina-Araujo, José A. Colina-Chourio. 
Utilidad diagnóstica del método de Kramer para la detección clínica  de la 
hiperbilirrubinemia neonatal. Investigación Clínica 2012 
(http://www.scielo.org.ve/scielo.php?script=sci_arttext&pid=S0535-
51332012000200004). 
35. Knudsen A, Brodersen R. Skin colour and bilirubin in neonates. Arch Dis Child 
1989;64(4):605-9. DOI: 10.1136/adc.64.4.605. 

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36. Slusher TM, Zamora TG, Appiah D, et al. Burden of severe neonatal jaundice: a 
systematic review and meta-analysis. BMJ Paediatr Open 2017;1(1):e000105. DOI: 
10.1136/bmjpo-2017-000105. 
37. Olusanya BO, Kaplan M, Hansen TWR. Neonatal hyperbilirubinaemia: a global 
perspective. Lancet Child Adolesc Health 2018;2(8):610-620. DOI: 10.1016/S2352-
4642(18)30139-1. 
38. Donneborg ML, Hansen BM, Vandborg PK, Rodrigo-Domingo M, Ebbesen F. 
Extreme neonatal hyperbilirubinemia and kernicterus spectrum disorder in Denmark 
during the years 2000-2015. J Perinatol 2020;40(2):194-202. DOI: 10.1038/s41372-
019-0566-8. 
39. Olusanya BO, Teeple S, Kassebaum NJ. The Contribution of Neonatal Jaundice to 
Global Child Mortality: Findings From the GBD 2016 Study. Pediatrics 2018;141(2). 
DOI: 10.1542/peds.2017-1471. 
40. Olusanya BO, Osibanjo FB, Mabogunje CA, Slusher TM, Olowe SA. The burden and 
management of neonatal jaundice in Nigeria: A scoping review of the literature. Niger 
J Clin Pract 2016;19(1):1-17. DOI: 10.4103/1119-3077.173703. 
41. Simiyu DE. Morbidity and mortality of neonates admitted in general paediatric wards 
at Kenyatta National Hospital. East Afr Med J 2003;80(12):611-6. DOI: 
10.4314/eamj.v80i12.8776. 
42. Mwaniki MK, Gatakaa HW, Mturi FN, et al. An increase in the burden of neonatal 
admissions to a rural district hospital in Kenya over 19 years. BMC Public Health 
2010;10:591. DOI: 10.1186/1471-2458-10-591. 
43. Nyangabyaki-Twesigye C, Mworozi E, Namisi C, et al. Prevalence, factors associated 
and treatment outcome of hyperbilirubinaemia in neonates admitted to St Francis 
hospital, Nsambya, Uganda: a descriptive study. Afr Health Sci 2020;20(1):397-405. 
DOI: 10.4314/ahs.v20i1.46. 
44. Donneborg ML, Hansen BM, Petersen JP, Vandborg PK, Ebbesen F. [An update on 
unconjugated neonatal hyperbilirubinaemia in Denmark]. Ugeskr Laeger 
2020;182(14a) (In dan). 

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45. Qattea I, Farghaly MAA, Elgendy M, Mohamed MA, Aly H. Neonatal 
hyperbilirubinemia and bilirubin neurotoxicity in hospitalized neonates: analysis of 
the US Database. Pediatr Res 2022;91(7):1662-1668. DOI: 10.1038/s41390-021-
01692-3. 
46. Manning D, Todd P, Maxwell M, Jane Platt M. Prospective surveillance study of 
severe hyperbilirubinaemia in the newborn in the UK and Ireland. Arch Dis Child 
Fetal Neonatal Ed 2007;92(5):F342-6. DOI: 10.1136/adc.2006.105361. 
47. McGillivray A, Polverino J, Badawi N, Evans N. Prospective Surveillance of Extreme 
Neonatal Hyperbilirubinemia in Australia. J Pediatr 2016;168:82-87 e3. DOI: 
10.1016/j.jpeds.2015.08.048. 
 
 
 

Date of document: March 1, 2023 
 
24
Appendices 
 
Appendix I: Active timeline 
 
 
 
Application for Ethical Review from Danish NVK 
September 2022 
Application for Ethical Review from Princess Marina 
Hospital REC and Ministry of Health and Welfare  
September 2022 
 
Data collection 
March 2023 - May 2024 
Data analysis 
June 204 
Report writing and dissemination of results 
June - September 2024 
 
 
Appendix II: Estimated budget (DKK) 
 
 
 
 
Purpose 
Budget (DKK) 
Travel t/r Botswana (Julie Zimmer) 
20 000 
Residency in Botswana (Julie Zimmer, 3 weeks) 
7 000 
Expenses to personnel in Botswana 
40 000 
Expenses to blood analysis in Botswana 
30 000 
Other operating expenses in Botswana (contingency)  
3 000 
Total 
100 000 

Date of document: March 1, 2023 
 
25
Appendix III: English version of the consent form 
 
Primary consent form: 
 
STUDY TITLE 
Evaluation of bilirubin estimates in newborns from smartphone digital images in a population 
in Botswana.  
 
Lead investigator  
Julie Zimmer, University of Copenhagen, juzim@online.no, +47 95102393 
 
Supervisor  
Britt Nakstad, professor and head of neonatology, tel 76682945 
Lizzy Pezwa, resident in paediatrics, tel 74608559 
Mammule Tau, resident in paediatrics, tel 75355407 
 
Background and rationale for the study 
This research project is about a smartphone application that can be used to identify Jaundice, a 
potentially dangerous condition caused by too much of a yellowish waste product called 
bilirubin that causes the skin to appear yellow. Jaundice is common among newborns and is in 
most cases self-limiting and harmless. However, when severe and unrecognized it can be fatal 
or cause serious brain injury. The measurement of bilirubin is normally done with blood 
samples. We want to try out a model that estimates bilirubin using smartphones. This may 
potentially save many lives and reduce the number of children with disabilities  
 
Purpose of this research study 
The purpose of this research study is to see how effective the smartphone application is in 
identifying neonatal jaundice. To find out if the mobile app is reliable, we need to test many 
newborns, so we invite you to participate.  
 
Procedure 
The study is being conducted at Princess Marina Hospital. Before you take part in this research 
study, the study must be explained to you, and you must be given the chance to ask questions. 
You must read and sign this informed consent form.  
To check if your baby is jaundiced, we ask to take a photo of your baby’s breast using a 
smartphone and analyze the skin color in the picture. We will take a picture of the skin of the 
chest while your baby is lying on its back on the examination table. The face of your child will 
not be visible in the picture This will be done while collecting blood obtained by a puncture in 
the baby’s skin. Lastly, we compare the 2 methods for measuring bilirubin.  
 
Length of your participation 
The photo and sampling for bilirubin measurement will last a maximum of an hour. If jaundice 
is identified, treatment will be started. 

Date of document: March 1, 2023 
 
26
 
Cost and compensation 
By signing this consent form, you will not waive any of your legal rights or release the parties 
involved in this study from liability for negligence.  
 
Possible risks or discomforts by taking part in this study 
The risks and discomforts brought about by this study are minimal. Taking smartphone images 
involves no risk or pain and blood sampling is routine when jaundice is suspected.  
 
Possible benefits to you for taking part in this study 
As a participant in this study, we may get results from photographing indicating that your child 
will need treatment for jaundice.  
 
Voluntary participation 
Your participation in this study is voluntary. If you decide to take part in this study, we ask for 
your signature on the consent form. You are free to withdraw from this study at any time. 
Withdrawing from this study will not affect your relationship with the researcher, if any. If you 
withdraw from the study before data collection is completed, your data will be returned to you 
or destroyed. 
 
Confidentiality  
The results related to your child will be anonymous. Participant data will be kept confidential 
except in cases where the researcher is legally obligated to report specific incidents.  
 
Contact information  
If you have any questions relating to the study or your participation you may contact dr. Lizzy 
Pezwa or dr. Mammule Tau, or prof. Britt Nakstad, or nurses and doctors in the ward, or the 
lead investigator Julie Zimmer. Their details are noted on the first page.  
_____________________________________________________________________ 
Consent  
I certify that I have had the study form explained to me, have read or have had read to me the 
information describing the procedures, benefits, and risks of the study, as well as this consent 
form. I have been given an opportunity to ask questions about the study, which have been 
answered to my satisfaction. I understand that my participation is voluntary and that I am free 
to withdraw at any time, without giving a reason and without cost. I understand that I will be 
given a copy of this consent form. I voluntarily agree to allow my child to take part in this study.  
 
Participant's signature   
______________________________   
Date __________  
 
Investigator's signature   
_____________________________  
 
Date __________  

Date of document: March 1, 2023 
 
27
Secondary consent form: 
 
Title of Project:  
Evaluation of bilirubin estimates in newborns from smartphone digital images in a population in 
Botswana.  
 
Name of researchers responsible for the project:  
Julie Zimmer and Britt Nakstad 
 
 
 
 
 
 
 
 
 
Printed name of participant  
 
         Signature of participant                           Date  
 
 
 
 
 
 
    Printed name of person obtaining consent 
        Signature of person obtaining consent         Date 
 
 
 
Statement  
Please initial each box 
I confirm that I have read the information sheet version 1.1 for the above-named study.  I 
have had the opportunity to consider the information, ask questions and have these 
answered satisfactorily.  
 
I understand that my participation is voluntary and that I am free to withdraw at any time 
without giving any reason. 
 
I agree to be recorded during the interviews and understand the original recording will be 
destroyed once the interview is transcribed and verified.   
 
I agree for quotations to be used in any report or paper. I understand that the use of my 
quotations in any report or paper will be anonymous and not attributable to me.  
 
I agree for anonymized transcripts to be used for future research outputs. 
 
I agree to take part in the above-named study 
 

Date of document: March 1, 2023 
 
28
Appendix iV: Standard operating procedure 
 
1. Obtain written informed consent from the participants.  
2. Collect background data such as: birth weight, gender, age on examination, gestational 
age, type of feeding, and Fitzpatrick scale score, newborn Neomar’s scale score.  
3. Using a transcutaneous bilirubinometer Dräger Jaundice Meter JM-105 obtain and 
record bilirubin estimates.  
4. Take three measurements of skin reflectance using a CE-marked portable Konica 
Minolta spectrophotometer CM-700d by placing it on the newborn’s chest.  
5. Place the Picterus Calibration Card on the chest of the newborn with the sticky side 
facing down and with its hole over the infant’s sternum.  
6. Collect digital images using a validated smartphone with Picterus JP. Once the phone 
is aligned with the card, capture two sets of 6 images, 3 without flash and 3 with flash.  
7. Within 60 minutes of obtaining the images, collect a blood sample for TSB estimation 
and send to the hospital lab for processing.  
8. Carryout a second TSB measurement with the neonatal bilirubin analyzer Neo-Bil 
Plus from DAS. Collect10 μl of blood in a heparinized capillary tube for analysis in 
the Neo-Bil Plus equipment.  
 
 

Date of document: March 1, 2023 
 
29
Appendix V: Literature review 
 
1. Correlations 
 
1.1 The correlation between bilirubin estimates from a smartphone application and 
bilirubin measurements in serum in newborns with varying degrees of jaundice 
 
One of the first attempts to implement an alternative diagnostic approach was made by a group 
of researchers from Thailand who designed a non-invasive method for measuring bilirubin 
levels in 61 newborns. Images of the chest were obtained using a digital camera and manually 
inspected and adjusted in Photoshop. They found a significant (p<0.05) Pearson correlation of 
0.86 between serum bilirubin and bilirubin estimated values obtained from the images. 25 
 
Using a digital camera to obtain images of the sclera in 110 newborns, Leung et al. showed a 
Pearson correlation of 0.75 between the sclera color and total serum bilirubin (TSB) level, 
concluding that although such correlation is not high enough to be used to predict the absolute 
TSB level, their technique may be helpful as a screening method to identify newborns with TSB 
above 205 μmol/L. 26 
 
In 2014, De Greef et al. reported the first results of BiliCam, a low-cost smartphone-based 
medical device that uses an embedded camera and a paper color calibration card. They 
conducted a study on 100 newborns to correlate BiliCam bilirubin estimates with TSB levels 
and Transcutaneous bilirubinometer (TcB) results. They concluded that BiliCam could not 
substitute TSB testing. Still, they showed statistically equivalent performance as the TcB, so it 
can be used as an effective screening tool to decide whether TSB testing is needed. Later on, 
the same group reported the results of a sample of 530 newborns with different ethnicities, 
including white, African American, Hispanic and Asian American, with an overall correlation 
of 0.91 - and 0.91, 0.90, and 0.88 for each group, respectively. Using two decision rules, 
sensitivities in identifying newborns with high TSB were 84.6% and 100%, and specificities 
were 75.1% and 76.4%, concluding that BiliCam provides precise estimates of TSB levels and 
can be used to effectively screen newborns for jaundice. 27  
 
There have been suggested different algorithms for the decision support systems of the 
applications. A study from Turkey reported the results of an advanced image processing 

Date of document: March 1, 2023 
 
30
technology along with a color calibration card to analyze smartphone images of 40 healthy and 
40 jaundiced newborns. It showed that the obtained bilirubin estimates were consistent with 
TSB results with a compliance rate of 85%. A more recent Turkish study from 2021 shows that 
using an algorithm based on the deep-learning classification of infants can help improve the 
results for server-based applications. The study classified the newborns into two groups 
according to their bilirubin levels, created a training model for the algorithm, and tested this on 
40 subjects. The two-group classification accuracy of the developed algorithm was 92.5% for 
this 40-subject test group. Thus, they concluded that server-based estimations of neonatal 
jaundice could be estimated by a deep-learning-based classification followed by multiple linear 
regression. 28  
 
In Norway, a group of researchers developed a smartphone application based on professor 
Randeberg’s research on bio-optics. Using a novel color calibration card that reflects 
differences in newborn skin color with varying degrees of melanin and bilirubin, a clinical trial 
on 134 Caucasian newborns showed a good correlation with TSB of 0.84. 20 
 
In 2020, the Chinese smartphone app BiliScan was tested on 369 Chinese Asian newborns. This 
study showed a moderate agreement with a correlation of 0.5 and concluded that the app 
required additional improvements for accurate measurements across wider ranges of TSB. A 
validation study of the app in 2021 showed a moderate agreement with a correlation of 0.6, and 
it was concluded that BiliScan tends to overestimate TSB and cannot replace it. However, it is 
an available method that can help to recognize jaundice in an early phase and minimize the 
number of invasive pricks. 29 
 
Although a huge step has been taken to achieve the need for an affordable and available method 
for neonatal jaundice, there are still gaps to have the ideal one, which may have the same 
accuracy in all types of skin and can be used on any smartphone.  
 
 

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31
1.2 The correlation between bilirubin estimates from a smartphone application and 
bilirubin estimates from a standard transcutaneous device in newborns with varying 
degrees of jaundice 
 
In 2016 Rong et al. used an automated smartphone image-based bilirubin system (AIB) and a 
color calibration card for predicting jaundice and compared the results with TcB and TSB in 
215 preterm and term neonates. There was no significant difference between AIB, and a 
correlation of 0.503 for the whole population and 0.628 for term neonates was found. 30 
 
One year later, another Chinese group assessed the accuracy of the same AIB system using the 
smartphone app Biliscan for Newborn Jaundice and compared results with TSB and TcB of 
296 datasets from 194 neonates. The accuracy of AIB was not inferior to TcB, and the TSB 
value was < 20 mg/dL, but it decreased with higher bilirubin values. The correlation between 
AIB and TSB was 0.824, so it was concluded that Biliscan for Newborn Jaundice is useful for 
dynamic monitoring moderate jaundice of neonates and early infants at home. 31 Nowadays, 
this application is available online for free. Its accuracy and reliability have been tested in an 
Indian population of 35 neonates, taking images of the sternum and abdomen. They found a 
correlation of 0.6 for the sternum and 0.55 for the abdomen. 32 
 
1.3 The correlation between bilirubin estimates from a smartphone application and 
bilirubin estimates from a visual inspection in newborns with varying degrees of 
jaundice 
 
To our knowledge, there are no studies that present a comparison between bilirubin estimates 
made by a smartphone application and bilirubin estimates from a visual inspection in newborns. 
However, some studies present results of the correlation between visual inspection and TSB. 
Moyer et al. studied the correlation among 244 observations made by 2 groups of health workers 
and bilirubin levels in infants with gestational age > 36 weeks. Bilirubin ranged from 0.4 to 
16.7 mg/dL. They found a Pearson coefficient of 0.43 and 0.54 for the 2 groups of observers 
when comparing the visual assessment and TSB. However, the agreement between observers 
regarding the presence of jaundice was low.  
 
Another finding was that the presence of any visible jaundice beyond the lower chest (between 
nipples and umbilicus) had the best combination of sensitivity and specificity for a 12 mg/dL 

Date of document: March 1, 2023 
 
32
bilirubin value, suggesting that infants without jaundice below the nipple line were not likely 
to have a 12 mg/dL or higher bilirubin value. However, 81% of infants with bilirubin values 
less than 12 mg/dL also presented jaundice below the nipple line, concluding that this 
observation was only useful to exclude high bilirubin levels and that visual assessment is neither 
accurate nor reliable for neonatal jaundice diagnosis. 33 
 
In another study, five neonatologists and 17 nurses made 3532 visual clinical assessments with 
the principle of cephalocaudal progression, named BiliEye, in 1129 term and late term infants 
(> 35 weeks) before discharge from the hospital on days 2 to 5 of life. The level of TSB was 
measured at the same time. Although a good correlation (0.752) between BiliEye and TSB was 
found, it was concluded that visual assessment is not a reliable screening tool for significant 
neonatal hyperbilirubinemia before discharge. Neonates with TSB levels in high-risk zones 
may be misdiagnosed as low-risk with inadequate follow-up. 9 
 
However, in 2012 Acosta-Torres et al. compared Kramer’s scale values with TSB in 50 
newborns with NNJ of 3 different ethnic groups (Caucasian, indigenous, and African-
American). They found a correlation index of 0.93 (p<0.005) and no differences among 
ethnicities, concluding that Kramer’s scale is a safe, non-invasive, and costless method that 
helps prevent kernicterus and should be implemented in health facilities lacking 
bilirubinometers. 34 
 
Some other considerations have been made regarding skin color. Knudsen and Brodersen 
concluded that measuring yellow color in the skin is not a reliable indicator of high bilirubin 
levels because it depends upon other factors such as plasma pH, albumin concentration, and 
basic skin color bilirubin concentration. 35 
 
 

Date of document: March 1, 2023 
 
33
2. Epidemiology 
 
2.1 The global and regional incidences of neonatal hyperbilirubinemia 
 
The global incidence of severe neonatal hyperbilirubinemia has been estimated in two studies 
of large datasets. Bhutani et al.2, was the first to first to do this and was published in 2013. They 
used a mathematical model for its estimations and concluded with a global incidence of 359 per 
100 000 births. They included incidences of extreme neonatal hyperbilirubinemia, defined as 
“TSB ≥ 428 μmol/L or those treated with exchange blood transfusion”  
 
Another study, done by Slusher et al.36, was published in 2017 and relied on population-based 
studies in numerous countries worldwide for its estimation. They concluded with a global 
incidence of 99 per 100 000 births and included incidences of neonates with severe neonatal 
jaundice, defined as “jaundice associated 
with acute bilirubin 
encephalopathy 
(ABE)/kernicterus and/or exchange transfusions (ET) and/or jaundice-related death”.  
 
Regionally, the incidences of neonatal hyperbilirubinemia have been tried to be estimated in 
numerous studies worldwide. However, the definitions of neonatal hyperbilirubinemia vary for 
many studies and are therefore difficult to compare. Generally, it can be seen that low-income 
countries use definitions of neonatal hyperbilirubinemia with lower TSB values (TSB ≥ 170) 
compared to high-income countries (TSB ≥ 425-510). Additionally, the studies take different 
approaches on data collection. Some studies are conducted on a single population in the 
respective country, while other studies retract information from previously written articles, 
databases provided at the hospital, or reports they receive from clinicians. Generally, low-
income countries tend to rely on information from medical forms with limited laboratory 
investigations, while high-income countries use databases. 
 
Table 1 shows incidences estimated in five studies from low-income countries and eight studies 
from high-income countries. Their results demonstrate that high-income countries generally 
have lower incidences of severe neonatal hyperbilirubinemia ranging from 7.1-42 per 100 000 
births compared to low-income countries, with incidences of neonatal hyperbilirubinemia 
ranging from 5.5-34%. However, there are numerous limitations to this conclusion such as the 
limited quality of the studies from low-income countries, the lacking definitions of 
hyperbilirubinemia in some of the studies, and variation in population included in the studies.  

Date of document: March 1, 2023 
 
34
Table 1: Incidences of neonatal hyperbilirubinemia. 
 
 
 
 
Study 
Country 
Definition 
Incidence 
CI 
Olusanya et al. 
Nigeria 
TSB ≥ 170 μmol/L 
5.5% 
4.9-6.2 
Worke et al. 
Ethiopia 
- 
42.4%  
(of all complications) 
- 
Simiyua et al. 
Kenya 
“jaundice”  
34.4%  
- 
Mwaniki et al. 
Kenya 
“jaundice” 
9.2% 
- 
Nyangabyaki-
Twesigye et al. 
Uganda 
TSB ≥ 170 μmol/L 
7.75% 
- 
Donneborg et al. 
Denmark 
TSB ≥ 450 μmol/L 
42 / 100 000 
28-69 / 100 000 
Qattea et al. 
US 
P59.9 Diagnoses 
Neonatal 
hyperbilirubinemia 
19.6% 
- 
Sgro et al. 
Canada 
TSB ≥ 425 μmol/L 
40 / 100 000 (1) 
12 / 100 000 (2) 
- 
Manning et al. 
UK 
TSB ≥ 510 μmol/L 
7.1 / 100 000 
5.8-8.6 / 100 000 
McGillivray et al. 
Australia 
TSB ≥ 450 μmol/L 
9.4 / 100 000 
- 
Bhutani et al. 
California 
TSB ≥ 428 μmol/L 
19.2 / 100 000 
- 
Zoubir et al.  
Switzerland 
TSB ≥ 425 μmol/L 
17 / 100 000 
- 

Date of document: March 1, 2023 
 
35
2.2 The global and regional morbidity and mortality of neonatal hyperbilirubinemia  
 
The global incidence of kernicterus has been estimated in the same study by Bhutani et al.2 
from 2013 to be 56 per 100 000 births, with a higher incidence in low-income countries (73 per 
100 000) than in high-income countries (10 per 100 000). In another four regional studies from 
high-income countries, the incidence ranged from 0.6-13.6 per 100 000 births. 
 
The global mortality rate of deaths caused by neonatal hyperbilirubinemia was estimated in the 
study of Bhutani et al2 to be 114 000 deaths (out of 134 million). They also found this to be 
higher in low-income countries (119 per 100 000 births) compared to high-income countries (1 
per 100 000 births).  
 
Another study, by Olusanya et al.37 looked at the data from the Global Burden of Disease study 
from 2016, a large dataset provided by researchers who review multiple studies worldwide and 
integrate these into one large dataset. From this dataset, Olusanya et al. concluded a mortality 
rate of 1496 per 100 000 births owed to neonatal hyperbilirubinemia. 
 
Regional mortality rates are continually being issued in order to provide clinicians with tools 
to prevent avoidable deaths. In four studies from low-income countries, it was found a mortality 
rate ranging from 1.3-13.1% compared to a mortality rate from 0-0.03% in two studies from 
high-income countries. Several studies from high-income countries did not provide numbers 
for mortality, probably because there were none. For example, a large study done in Denmark, 
by Donneborg et al.38 found that none of the 12 infants who acquired kernicterus spectrum 
disorder (KSD) died. All of these findings on morbidity and mortality are summarized in Table 
3. 
 
 

Date of document: March 1, 2023 
 
36
Table 3: Mortality rates and kernicterus/bilirubin encephalopathy cases. The first three studies base 
their mortality rates on all births, while the. 
 
Study 
Country 
Mortality rate 
Kernicterus 
Bhutani et al.2 
Global 
114 000 / 134 million 
119 / 100 000 (1) 
1 / 100 000 (2) 
56 / 100 000 
73 / 100 000 (1) 
10 / 100 000 (2)  
Olusanya et al.37  
Global 
1496 / 100 000 
1309 / 100 000 (3) 
187 / 100 000 (4) 
113 401 DALYs lost (5) 
Olusanya et al.39 
Global 
7th cause of death (3) 
9th cause of death (4) 
- 
Olusanya et al.40 
Nigeria 
4-13.1 % 
- 
Simiyu et a.l41 
Kenya 
7.8 % 
- 
Mwaniki et al.42 
Kenya 
1.2 % 
- 
Nyangabyaki-
Twesigye et al.43 
Uganda 
1.9 % 
- 
Donneborg et al.38,44  
Denmark 
0 
1.2 / 100 000 
Qattea et al.45 
US 
0.03 % 
13.6 / 100 000 
Manning et al.46 
UK 
0.2 / 100 000 
0.9 / 100 000 
McGillivray et al.47 
Australia 
0 
0.6 / 100 000