A longitudinal cohort study of breastfeeding practices was undertaken in the Xinjiang Uygur Autonomous Region, PR China. Mothers who delivered babies during 2003 and 2004 were interviewed while in hospital and were invited to participate in the study. The mothers were assured that all of the personal data collected would be kept confidential. After their return home mothers were contacted in person or by telephone at approximately monthly intervals (at 0.5, 1.5, 2.5, 3.5, 4.5 and 6 months respectively) and asked to complete a structured questionnaire to obtain details of breastfeeding practices.
A total of 1256 mothers were recruited from five hospitals and institutes located in urban areas(Shihezi People's Hospital, Shihezi Maternal and Child Health Care Institute, Urumqi Maternal and Child Health Care Institute) and rural areas (Chabuchaer Maternal and Child Health Care Institute and Yumin County Hospital) of the province. These hospitals and institutes covered majority of mothers who delivered babies in the cities and suburbs. About 70% mothers in Shihezi city and suburb delivered babies in Shihezi People's Hospital (about 50%) and Shihezi Maternal and Child Health Care Institute(about 20%). More than half Uygur babies in Urumqi were born in Urumqi Maternal and Child Health Care Institute. More than 50% babies in Chabuchaer and more than 60% in Yumin were born in Chabuchaer Maternal and Child Health Care Institute and Yumin County Hospital respectively. Maternal and Child Health Care Institutes in this study were woman's hospitals and also child health care centres. In Shihezi People's Hospital, mothers were recruited every second days due to due to staffing constraints. In other hospitals, all mothers were invited to the study and 97% (1219) agree to participate. Urumqi is the capital city of Xinjiang where the Uygur ethnic group is in the majority, while Shihezi is a predominantly Han ethnic area. Chabuchaer and Yumin counties have a larger concentration of Kazakh people and other minorities.
The majority of participants, including the minority groups, could read and speak Chinese (Mandarin). The questionnaire was originally prepared in Mandarin, and was also translated into the Uygur language, which can also be understood by Kazakh mothers. For those who could not read Chinese, trained nurses, who were fluent in the ethnic languages, were available to help them complete the questionnaires. For all minority mothers, follow up calls and visits were made in their own ethnic languages by nurses from their own ethnic group.
The questionnaire was based on those developed by Scott, Binns and Duong that have been extensively used in breastfeeding cohort studies in Australia, Vietnam and Kenya [17–22]. The questionnaires were designed to identify the feeding method and to collect information on factors associated with breastfeeding. After translation the questionnaires were tested in focus groups to ensure cultural appropriateness.
The project was approved by the Xinjiang local research authorities (Shihezi University, Urumqi Science Research Committee) and the Human Research Ethics Committee of Curtin University, Australia. Mothers who agreed to participate in the study signed the consent page in front of the questionnaire and were informed of their rights to withdraw from the follow up process at anytime without prejudice.
The sample size needed was calculated to be 860 to give a difference of eight percentage points in breastfeeding rates between the Han and Uygur groups at six months. (confidence 95%, power 80%), assuming the breastfeeding rate to be 75% in the Han Chinese. Additional numbers were included because of the other ethnic groups in the sample. All data analyses were carried out using the Statistical Package for Social Science (SPSS), release 12.0 (SPSS Inc., Chicago, IL, USA). Descriptive statistics and cross tabulations were generated for demographic variables, life tables were used for breastfeeding rates and Kaplan-Meier model was used to calculate mean of 'exclusive breastfeeding' and 'full breastfeeding' duration and assessed the differences in different ethnic groups. 'Significant' means p value less than 0.05.
The definitions of breastfeeding used in this paper are: [23–25]:
'Any breastfeeding': The child has received breastmilk (direct from the breast or expressed) with or without other drink, formula or other infant food.
'Exclusive breastfeeding': Breastfeeding while giving no other food or liquid, not even water, with the exception of drops or syrups consisting of vitamins, mineral supplements or medicine.
'Predominant breastfeeding': In addition to breastmilk the infant may receive small amounts of culturally valued supplement – water, water-based drinks, fruit juice, and ritualistic fluids.
'Full breastfeeding' includes 'exclusive breastfeeding' and 'predominant breastfeeding'.