Facilitators and barriers to cervical cancer screening among ethnic minority women in Hong Kong: A qualitative study

Chui-ying Fong 方翠瑩，Lai-shan Chu 朱麗珊，Wan Luk 陸雲

HK Pract 2021;43:105-118

Summary

Objective: To explore the attitudes and barriers to cervical cancer screen among ethnic minority women in Hong Kong.
Design: Qualitative study using individual face-to-face semi-structured interviews
Subjects: Non-Chinese Hong Kong female residents aged 25-64 years who ever had sexual experience
Main outcome measures:
Subjects’ demographic data. Thematic analysis of their views and barriers towards cervical cancer and cervical cancer screening.
Results: All 30 interviewees aged 27-58 were interviewed between October 2018 and February 2019. They were of Filipino, Indonesian, Nepalese, Pakistani, Indian and Caucasian ethnicities. 15 of them have had a Pap smear done before. Many of them had past experiences that were unpleasant. However, most subjects expressed willingness for future Pap smear. The greatest motivations for them to have Pap smear performed were their having personal health assurance and they had professional recommendation. The barriers to cervical cancer screening included health illiteracy, restrictions in the public system, language barrier, practicality and emotional states. Facilitators included community-based education, multi-lingual and simplified booking system, and extended affordable Pap smear services on public holidays.

Keywords: facilitators, barriers, cervical cancer screening, ethnic minority, qualitative study

摘要

目標: 探討在港少數族裔婦女對子宮頸癌篩查的態度和障礙。
設計: 透過半系統式面談，將資料作定性研究。
對象: 25-64歲曾有性經驗的非華裔女性香港居民。
主要測量内容:
分析她們對子宮頸癌及篩查的看法和實行篩查的障礙。受訪者的人口統計學上資料。
結果: 在2018年10月至2019年2月期間，訪問了30名菲律賓、印尼、尼泊爾、巴基斯坦、印度等族裔和白人婦女。受訪者年齡介乎27至58歲。半數受訪者（N=15）曾接受子宮頸抹片檢查。雖然很多受訪者對過去檢查感到不滿，但大多數仍表示願意在日後再作抹片檢查。推動她們進行檢查的最大因素是為保障個人健康和專業人士推薦。而子宮頸癌篩查的障礙包括缺乏健康知識、公營服務在運作上的限制、言語不便、檢查時引起的恐懼和尷尬。在少數族裔社群推廣健康教育、採用多國語言的和簡化的預約系統、在假期時提供服務，可促使更多婦女接受子宮頸癌篩查。
結論: 為不同少數族裔社群提供多種語言的健康資訊，可以改善她們對疾病的認識和公共醫療服務的了解。以社區為基礎推行子宮頸癌健康教育和服務，可助她們解決在言語上和檢查過程中的各種障礙。

關鍵字: 推廣方法，障礙，子宮頸癌篩查，少數族裔，定性研究

Introduction

In Hong Kong (HK), ethnic minorities (EM) refer to persons who report themselves as of non-Chinese ethnicity in the population census. ¹ They constitute 8% of HK’s population and its number has increased by more than 70% over 10 years to 584,383 in 2016.

The three largest ethnic groups were the Filipino (31.5%), Indonesian (26.2%) and South Asians (14.5%), which include Indians, Nepalese, Bangladeshis and Sri-Lankans. More than half of the EM group (320,790 persons, 54.9%) are women employed as domestic helpers.

Malignant tumours is the top leading cause of death in HK.² Among all local women, cervical cancer (CC) was the 7^th commonest cancer in 2016, and the 9th leading cancer mortality in 2017.³ Globally, CC is the 4^th commonest cancer in women, with higher disease burden in less developed regions such as Africa, India, and South-east Asia.⁴

Low-income local Chinese, new immigrants from Mainland China and EM women were found to have a significantly higher prevalence of cervical cancer screening (CCS) abnormalities.⁵ Among them, being South Asian (Indian, Pakistani, Sri Lankan, Nepalese and Bangledeshi) and South-east Asian (Indonesian, Filipino and Thai) had 6- to 11-fold increased risk of abnormal CCS compared with the local HK Chinese population.

Cervical cancer screening is an effective method to detect pre-cancerous lesions and prevent cervical cancer. Cytologic screening is the most important factor to reduce the risk of progression from herpes papilloma virus ( HPV) infection to invasive CC.⁶ However, CCS uptake remains low globally, especially among EM in many populations.^7-9 In HK, 60.5% of women aged 25 to 64 have ever screened for CC. Most asymptomatic women (55%) had their Pap smear (PS) performed at private clinics and 76.7% of them had their last PS within the preceding 36 months.¹⁰ The regular PS uptake (PS done within the last 3 years) was reported to be 63.9% among Chinese women in HK.¹¹ On the contrary, 61.2% of EM women have never had a PS.⁵ The ever-screened rate among South Asians was significantly lower than the general public (36% VS 48%) in HK.¹

Low socioeconomic status, low education level, low health literacy, older age, language barriers, not having a female provider, being an immigrant, short duration of residence and lower perceived risk of CC have been demonstrated to be associated with non-attendance for PS among the EM population.^5,8,13-15 The cost of attending PS, including transportation, the service itself and taking time off work, may be unaffordable for some EM women. Low level of acculturation (which encompassed language, ethnic identity, friendship choices, duration of residence, etc.) was suggested to affect uptake of screening.¹³ A review of foreign female domestic workers suggested that the governments of both labour-sending as well as host countries should have policies adjusted to facilitate the workers’ health.¹⁶

Cognitive, emotional and procedural-related factors have been commonly reported as barriers to PS in different populations^{8,11,15,17-20}, whereas some factors are ethnicity-specific. Lack of usual sources of care, practical issues, language barriers, fatalistic attitude and peer recommendations have mainly been observed in Asian groups.^13,18-20

Family history of cancer and having a positive relationship with doctors were facilitators identified only in the black populations¹³. Lack of a national CCS programme was highlighted to cause low screening rates in Nepal and the United Arab Emirates.^21,22

The EM groups in overseas studies included African American, Caribbean, Chinese American, Korean, East European, Hispanic women, Indian, Pakistani, Somali, Chinese Australian etc.^{7,8,13-15,17,19} They compared the CCS uptake rate and screening behaviour with reference to their Caucasian majority. Therefore, results from overseas studies may not be generalisable to Hong Kong, where Chinese are the majority and other Asians are the minority. A previous study focused on Filipino domestic helpers in HK.²³ Nowadays, the EM workers in HK can be from Indonesia, Nepal, Pakistan, India and even Caucasian countries and their barriers to regular cervical smear in HK have not been studied locally.

In order to enhance the services and policy for promoting regular CCS in the EM women’s social context, family physicians play an important role in promoting and performing CCS for patients in the primary care setting.

The aim of the current study is to explore the facilitators and barriers to cervical cancer screening among EM women in HK. By gaining a better understanding, culture-specific measures can be designed by both labour-sending countries and HK governments in order that cervical cancer screening will be improved and the health burden of cancer cases will be lessened.

Methodology

This study was approved by the Research Ethics Committee, Kowloon West Cluster, Hospital Authority, Hong Kong (Reference number KW/FR-18-089(125-05)).

This study was a qualitative study using semi-structured interviews. Open-ended questions were asked to explore the multi-level factors in depth, especially in a culturally diverse study population. Individual face-to-face interviews (Appendix 1) were conducted in community settings, including churches, non-profit community centers and an international school. Subjects’ personal experiences on Pap smear was first inquired. Afterwards, their reasons for attending or not attending CCS were explored in greater detail. All the interviews were conducted by the first author, a female doctor who received specialist training in family medicine.

The stury subjects’ baseline demographic data were collected (Appendix 2). Their idea on CC was assessed by a set of multiple-choice questions which was designed with reference to a questionnaire used in another local study¹¹ and a local CCS recommendation document.²⁴ The results were used to facilitate discussion if they had any misconceptions on CCS and CC.

The inclusion criteria were non-Chinese women aged 25-64 years who ever had sexual experience and with legal residency in HK.

Subjects with a present or past history of cervical cancer, had hysterectomy, mentally incapacitated and persons with active and unstable psychiatric illness were excluded.

Subjects were mostly recruited by purposive sampling between October 2018 and February 2019. To gain a broader range of views, a diverse spread of EM women were recruited to sample different ethnicities, occupations, ages and educational levels.

Filipino and Indonesian churches were first approached for subject recruitment since most Filipinos and some Indonesians in Hong Kong are Christians and churches are common gathering places on week-ends. Non-profit community centres that serve Indonesian domestic helpers and South-asian groups, mainly Indians, Pakistanis and Nepalese, were contacted for collaboration. Teachers from an international school were invited to participate in the study to enhance the diversity of ethnicities and socio-economic status of the subject pool. To increase sampling, we used a snowballing technique and invited subjects to introduce other subjects according to our targeted- subject characteristics.

Women were either invited by the organisation co-ordinators to join the study or those who responded to the first author after a face-to-face or saw our email description of the study. Subject recruitment was continued until data saturation. The target number was reached at 30 interviewees, which was consistent with the sample size recommended in literature.²⁵ A reward of $50 gift voucher was offered to every participant.

The information sheet and a written consent form were translated into Hindi, Urdu, Indonesian, Japanese and Korean for corresponding EM subjects. Subjects who could not communicate effectively in Cantonese, English or Mandarin were accompanied by an interpreter during the interviews with their consent. All the interpreters were arranged by the Non-government Organisations (NGOs). They were acquaintances of the participants to increase the participants’ comfort and confidence. They were either EM women themselves or were of EM descent and were therefore fluent in the EM languages to enhance the accuracy of the translation. The interviews were audio-taped and transcribed per verbatim. If an interpreter was present, the interpreted response was transcribed. The transcripts were returned to participants for comment if they consented and were reachable. Moreover, two of the authors checked the content validity between audio records and transcripts.

We used a semi-structured questionnaire to guide the interviews. Field notes were made during the interviews. Each interview session lasted 30-50 minutes, including introduction of the research, informed consent, interview, filling in questionnaire and performing the quiz. There were no repeat interviews. Transcripts were returned to some participants for comments and checking if the participants consented and were reachable.

The transcript was analysed manually using thematic analysis²⁶ by the first and second authors. After familiarisation with the data, a conceptual coding tree was developed. Transcripts were coded inductively. Common codes were categorised into themes which were iteratively revised in response to additional information. Close attention was paid to whether themes emerged exclusively or commonly among different EM women. Representative examples of each theme were extracted relating back to the research question. Both investigators read the transcripts and extracted the data separately. Inconsistency and disagreement among researchers was resolved by repeated textual reference, comparison and discussion. The final themes were reviewed and defined with mutually agreed names. Demographic data were analysed by descriptive statistics.

Data saturation was reached after 30 interviews and all interviewees were included for analysis. Mean age of the participants was 38.8 years (range 27 to 58). Twelve women attained tertiary education, followed by secondary (N=11) and primary (N=7) education. More than half of the subjects were domestic helpers (DoH) (N=17) and housewives (N=8). They were mostly married (N=23). Eighteen interviews were conducted in English and 4 in Cantonese. English interpretation was needed in 4 Indonesian, 3 Urdu and 1 Hindi interviews.

Summary of subject recruitment is shown in Table 1. Demographics of the participants are summarised in Table 2. Individual subject particulars are listed in Table 3. The knowledge score was the number of correct items scored in the quiz (full score 11). The range of score was 2 to 9 items.

Three themes were identified from the analysis (Table 4):

1) motivators for CCS:
 a) internal,
 b) external;

2) barriers to screening:
 a) health illiteracy,
 b) restriction of public system;
 c) language barrier
 d) practical barriers,
 e) emotional barriers,

3) enhancement strategies
 Participants’ identification number, ethnicity and age are put in parentheses following the quotes.

1) Motivators for CCS

All except two women expressed their intention to have PS. They felt reassured for good personal health reason and wished to have early diagnosis and treatment in case of any abnormality. Some of them reported they had personal history of cancers or other gynaecological diseases, making them more eager to perform PS.

“I would rather find out or catch it early when it was pre-cancers or when it’s actually cancer… it is also a form of reassurance... I’ve had skin cancer and my birth mother has had breast cancer... It’s not with cervical cancer but I’m just careful about that” (E01, American, 55)

“I think it is very important for every woman to have a pap smear, so we will know our body, if it’s still ok or something there.” (F05, Filipino, 48)

Having a family and medical professional recommendations further enhanced participants’ health awareness. Social and community support helped them take action to undergo PS.

“I have children…you definitely want to catch things early…because now there’s more people than just me” (E04, British, 33)

“doctor…told us also that it’s better we do the pap smear… my employer supports me… do the pap smear… even not Sunday, it’s on weekday, they just asked me to go, they pay with me” (F03, Filipino, 45)

“one community center… invite Asian ladies to join and to get to know awareness about this test… healthcare doctor, and she suggest… you should go and do this test… she give me the address and she book… pap smear test for me” (P04, Pakistani, 36)

2) Barriers to screening

Lack of awareness of PS was a major reason for never screening among 15 subjects. Misconceptions about CC and the screening schedule contributed to discontinuation of screening. For example, a few subjects thought they did not need to have a PS if they were currently sexually inactive or asymptomatic.

“because she doesn’t really have sexual activities… that’s why she wouldn’t go to have a pap smear… there’s no experience in doing it, so she has no idea what would happen” (I05, Indonesian, 40 (interpreter’s verbatim))

Most Filipino and Indonesian DoH are only free on Sundays and public holidays (PH), but most public PS providers are closed on those days.

“we have lack of time… because we only have one day-off a week, and normally public hospital is closed” (F04, Filipino, 34)

Some subjects also expressed difficulty in utilising the public services due to the inconvenient phone booking system, and unavailability of walk-in service

“It is hard to book on phone, by computer, even not by anyone… in emergency department you just directly go any time, but in the clinic, the phone, that is the problem first of all” (P04, Pakistani, 36)

Across different ethnic groups, not knowing where and how to receive PS service was commonly mentioned.

“I found in Hong Kong, the private doctors are really expensive; I wasn’t aware there was anywhere…I should do the testing here in Hong Kong until this time” (E02, British, 50)

“we don’t know where to go, and where to do the pap smear.” (F05, Filipino, 48)

For South Asian ladies, especially Pakistanis, language barrier significantly deterred them from booking and attending the service.

“our English is not too good, and that’s why she hesitate… to ask them in English, why we came here and what we want to do.” (P02, Pakistani, 31 (interpreter’s verbatim))

“She need interpretation… who will help me to get the appointment and I will go.” (P01, Pakistani, 27 (interpreter’s verbatim))

Lack of time due to job and family duties was frequently mentioned, especially most of the subjects were DoH and housewives. Forgetfulness due to busy schedule also hindered them from adhering to the screening schedule. The legislation in HK requires DoH to live in their employers’ residence.²⁷ It may not be easy for them to freely go out on weekdays.

“Sundays that she can go out to get a pap smear… for weekdays…they might have pay cuts… it’s mostly just the job because she is taking care of a child, so she can’t really leave the place.” (I08, Indonesian, 47 (interpreter’s verbatim))

Cost was a concern for numerous subjects, particularly at private clinics. However after knowing that the prices for PS in the public and semi-government clinics were around $100- 300, then most of them felt it was affordable.

“but here we need to pay a thousand dollars just for the pap smear or 800 dollars for the pap smear… So we cannot afford, especially if the employer would not like to… answer for that bill, so you need to do it yourself.” (F08, Filipino, 58)

Fear of the unpleasant procedure was a common barrier. Fear of abnormal result also made some subjects avoid the test. Subjects across difference ethnicities voiced out the preference for a female practitioner to perform the PS to lessen the embarrassment of exposing their private parts.

“I think it’s scared also. How they do this… I heard from some, they take some parts from inside” (N02, Nepalese, 30)

“embarrassment… I don’t feel really discomfort or pain…just prefer a lady doctor for this type of investigation.” (E02, British, 50)

3) Enhancement strategies

Numerous ladies expressed that more publicity targeting foreigners is needed to introduce the CCS programme. One subject reflected that she only learned about the CCS service after delivery and received post-natal service in Maternal and Child Health Center (MCHC), otherwise she had no idea about CCS service in HK.

“how I would have known… if it wasn’t because I gave birth. So, because I’m already in their clinic for… postnatal check-ups, then they tell me to come for the smears, so I don’t know how the system in Hong Kong works if you are just new into Hong Kong... they don’t get a reminder, they don’t get told”(E04, British, 33)

One subject also preferred to have PS in MCHC in spite of the fact that she could afford private PS service.

“I have the option I could have done it privately, but not everybody has an option…I think it’s easier to keep everything in the government clinic, because they have all my postnatal records and now they do my antenatal checks as well…it’s nice they have all my information.” (E04, British, 33)

Some EM women expressed difficulty in booking or attending PS in public clinics, so they welcome PS in community centres or churches on Sundays. Numerous subjects also appreciated the current research to educate and advocate for EM women.

“your study is very effective, it could help us… express what is in our heart…to tell the doctor… spare time for all of us …if there are churches that offer the room… will have people queuing for the pap smear” (F08, Filipino, 58)

Some subjects preferred a reminder system so that they would remember it amidst their busy schedule.

“I’m very busy at a certain time and then it tends to get put off… there’s reminder, I think that’s a really critical thing. Does the public hospital… send out little reminder cards?” (E01, American, 55)

Some subjects felt shy to have PS alone, therefore a group of EM women attending PS together can reduce the shyness.

“in our culture, this is a bit hesitate…if we go alone, we feel shyness… but if in group… if lady friends altogether… maybe the shyness will be less” (P02, Pakistani, 31 (interpreter’s verbatim))

Some highlighted the importance of health education to overcome the taboo and clarify misunderstanding.

“coz I’m kind of brought up in Hong Kong, so quite modern, so not too shy about these things… it’s important to… take care of yourself and do proper health screening” (N05, Indian, 30)

Discussion

The present study explored the positive and negative factors for cervial cancer screening among EM women in Hong Kong. To most of our subjects, cervical cancer implied mortality or significant morbidity which they would be afraid of and would have wanted to prevent. Therefore, the wish to ensure good health, prevent cancer and early disease detection was repeatedly mentioned as motivators to have CCS. Having a family and children further augmented their desire for a healthy life and minimal sufferings. The majority (28 out of 30) of subjects intended to have PS done as a means to early cancer detection, higher chance of survival and health reassurance.

Cognitive, practical and emotional barriers echoed findings from previous studies. Unawareness of CCS, misconception about CC, fear, embarrassment and preference for female practitioners were universal ideas across different ethnicities and cultures.^{8,11-13,15,17-19} Access to PS has been discussed in numerous studies, but the context was slightly different in different studies. Access to female doctors,¹⁵ cost^20,21,22 and geographical distance²¹ hindered the access to CCS in other communities but not in our study population. Access to free screening was suggested to be a facilitator in other studies^19,20 but most of our subjects responded that the cost of $100-$300 was affordable to them.

Regarding the knowledge on CC, none of the subjects got impeccable result. This echoed the theme of “health illiteracy” that knowledge gap existed at variable degrees in all the subjects. Therefore, education materials that highlight the importance of CCS and address various misconceptions on PS will be useful for women from all walks of life. Doctor recommendation and community health promotion classes can augment patients’ motivations to perform CCS and instill knowledge on the importance of CCS.

Various subjects preferred to have PS in the MCHC because of reasonable cost ($100), trust in the government system and preference to keep all health records in the public system. Since a large group of HK’s EM population is DoH, they are bound to their job duties during the week and are usually free on Sundays and PH. However, most public and semi-government PS providers, such as Department of Health (DH), the Family Planning Association of HK, United Christian Nethersole Community Health services, Tung Wah Group of Hospitals and the Chinese University of HK are closed on those days. Private CCS services available on Sunday may not be affordable for them.

On the other hand, most South Asian ladies are housewives and can attend weekday check-ups, but the language barriers and the complicated telephone booking system hindered them to action. Language barrier was also mentioned in another study. ¹⁵ For instance, interpretation service is available in MCHC, but the PS telephone booking system at the MCHC only offers Cantonese, English and Mandarin languages, so some EM women cannot book the service without interpretation. If they want to book other CCS providers, they also need an interpreter to communicate with the clinic staff in Chinese or English in the first place.

Department of Health operates a website (www.cervicalscrenning.gov.hk) that provides comprehensive information on CCS, educational resources and directory of PS providers. The website also displayed CCS factsheets and videos in 6 EM languages. Moreover, DH also maintains a Cervical Screening Information System (CSIS) for all women to register and get reminders about their CCS schedule. Those resources can tackle the health illiteracy and forgetfulness barriers. However, the PS provider directory and the CSIS are only available in Chinese and English versions, which cannot completely solve the language barrier for some EM groups. More importantly, most subjects were not aware of this information platform or the affordable CCS options prior to the current study. One subject received screening information from television advertisement (English channel), whereas some learned about CCS services after delivery or hospitalisation for gynaecological problems. The mass media seemed not an effective means to reach most our EM subjects.

Cervical cancer screening information and service gap may be bridged by Non-government Organisations (NGOs) that provide healthcare support to EM groups. Since most subjects receive CCS information passively rather than actively search for it, multilingual posters and leaflets delivered to EM communities, such as churches, EM community centers, churches, DoH employment agencies, Labour Department and embassies, may tackle the health illiteracy barrier and introduce the CCS website.

Subjects are willing to do PS if it is offered on PHs, in groups, and with interpretation service. Embassy, churches and community centres are favourable places mentioned by them but the service availability was irregular. Most subjects preferred public PS service due to its affordability, reliability and continuity of whole-person care. Education classes conducted in NGOs can introduce the various CCS service providers and provide booking assistance. Potential Sunday public PS clinics can enhance DoH’s attendance. These suggestions can tackle the “restriction of public system”, language, practical and emotional barriers. Similar to a previous studies, culturally acceptable and affordable mass screening programmes on Sundays were advocated for DoH²³ and community-based education were found effective to increase CCS uptake in Asian women overseas.²⁸ Local studies are needed to study the cost-effectiveness of community-based interventions in the complex multitudes of EM populations.

Strengths of our study include: 1) qualitative study allowed subjects to freely express their opinions and expressed multi-level factors associated with their screening behaviour; 2) the composition of our study participants grossly resembled the actual composition of EM population in HK (Filipino, Indonesian, South Asians and Caucasians); 3) the study was conducted in local NGOs rather than in the clinic setting, so it probably reflected the situation of the general public better; 4) to the authors’ knowledge, this is the first qualitative study on CCS that intended to include all EM groups in HK.

Limitations of our study include: 1) certain EM groups were not represented such as Japanese, Koreans, Thai, Vietnamese and Africans due to lack of recruitment; 2) most of the organisations involved in the study had Christian background, so there might be selection bias. However, Christians and Catholic accounted for less than half of the subject pool and a total of 5 religions and 1 atheist were represented; 3) the reward to participants might potentially influence participant selection; 4) the presence of multiple interpreters might hinder the fidelity of the study and affect the interpretation of the data as minor nuances in the responses could be missed; 5) the accuracy of the translation was not verified; 6) language barriers occurred in the 4 interviews conducted in Cantonese.

Further quantitative studies are needed to investigate the effects of various factors, such as education level, religious beliefs, income and knowledge, on screening behaviour in different EM groups. Interpreters should be arranged for EM subjects with language barriers and back translation can be applied to ensure the accuracy of the translation.

Conclusion

The EM population in Hong Kong has diverse backgrounds, thus requiring different culturally-specific strategies targeting different levels. At personal level, multilingual public health promotion can improve their knowledge on CC and the screening service available in HK. Medical professionals’ recommendation during individual patient encounter can educate and motivate them to action. At the clinic level, education seminars can be conducted to reinforce the medical professionals’ knowledge of CCS and emphasise the specific needs of EM women. Multilingual leaflets can be prepared to educate EM patients. At the community level, the three major EM groups in HK (Filipino, Indonesian and South Asians) have their own culture and communities. NGOs that serve different groups can offer education classes, group screening programme and assistance in public service booking to solve the shyness and language barriers. CCS information may be provided to new DoHs at their embassies or employment agencies. At a system level, efforts can be made to revise the existing telephone booking system and CSIS to incorporate multilingual options and to arrange an on-site interpretation service if needed. In addition, discussion between different healthcare stakeholders can be carried out to study the possibility of a public CCS clinic on Sundays at bi-monthly or seasonal intervals.

Acknowledgements

We would like to thank the follow organisations for subject recruitment and providing venue for interviews: Asian Outreach Hong Kong Ltd., Hong Kong Christian Service (Integrated Service Centre for Local South Asians (ISSA)), Li Po Chun United World College, Operation Mobilisation, Sunrise Christian Community HK, Solomon’s Porch Indonesia. We appreciate the Hong Kong College of Family Physicians for granting the trainee research fund to financially support this study. Special thanks are due to Dr Eric Lee, Dr SN Fu, Dr Thomas Dao, Dr Victor Ip, Dr Sydney Cheung and Dr Winnie Sy for their advice and guidance on this study.