Malaysia and Hawaii have several advantages for epidemiologic and laboratory studies on nasopharyngeal carcinoma. Both have multiethnic populations with different incidence rates of nasopharyngeal carcinoma and different life-styles. Malaysia has large populations of Chinese, Malaya, and Indians, and the number of cases of nasopharyngeal carcinoma at any one time is comparatively large. Incidence rates for 1968--72, age-standardized to the World population, for Guangdong hua (Cantonese Chinese) in Malaysia were 24.3/100,000 for males and 12.0/100,000 for females. In Hawaii, the ratio was 12.9/100,000 for males and 6.7/100,000 for females. The small number of cases in Hawaii would require that research in that State be conducted in collaboration with research elsewhere with larger case numbers.
PIP: Many countries have a wealth of population data already available for utilization. In launching family planning population programs on a national scale every country must establish a long range of integrated programs of evaluation and data collection which will measure the past, current, and future trends in fertility, mortality, and migration patterns. These demographic features and poupulation profiles will assist in charting the strategies, objectives, targets, and survey components to be implemented for the successful launching of a country-wide program. In Malaysia the 10-year period population census, vital registration systems, sample houshold surveys, immigration, emigration, industrialization records, and KAP surveys serve as a source for obtaining population data and for charting population programs. Attention is directed to the census and to essential features of a census as well as to vital registration systems. The population census is a "total process of collecting, compiling and publishing demographic, economic and social data pertaining at a specific time or times to all persons in a country or delimited territory." A census is conducted on a national scale and enumeration is done individually. In Malaysia a De Jure and a De Facto Census are normally conducted. Enumeration is carried out by means of direct interviews or canvasser methods. Malaysia's last census was conducted between May and June 1980. The organization aspects of administering a nationwide census is a long process which may take a couple of years in the planning period. While the census provides a picture on the population at 1 point in time, the vital registration system monitors the continuous process of vital events and performs dual functions: to register vital events and obtain vital records which are legal documents; and to collect statistics about vital events. In Malaysia the registration of births and deaths and marriages is compulsory. Vital statistics may also be obtained from household surveys.
PIP:
The International Fertility Research Program is carrying out several studies focused on breastfeeding's contraceptive protection. A longitudinal study is investigating the relationship between breastfeeding and the return of ovulation and fertility after childbirth. The impact of factors such as the early introduction of supplementary foods, resumption of menses, and sexual practices on the return of ovulation will be analyzed. The study, which will be conducted at 4 geographic sites, will include a total of 100 women who are breastfeeding and a control group of 40 nonlactating mothers. Its ultimate goal will be to determine the optimum time for breastfeeding women with different cultural needs to start using contraceptives. A second study will seek to determine whether progestogen-only oral contraceptives (OCs) have advantages for lactating women. Trials in India, Malaysia, Argentina, and Egypt will compare 1000 lactating women who use progestogen-only OCs with an equal number of women who use nonhormonal contraception in terms of contraceptive acceptance and side effects and infant weight gain. The third study will survey breastfeeding patterns in relation to changing child spacing trends in a sample of 4000 women from Lagos, Nigeria. Analyzed will be the proportions of women who are using a modern method of fertility control, the proportions protected from unwanted pregnancy by the traditional practices of prolonged breastfeeding and sexual abstinence, and determinants of recent changes in the prevalence and duration of breastfeeding.
The design of family studies to estimate the value of an intraclass correlation coefficient p is considered when ni individuals are to be selected from each of k families, i = 1, 2, ..., k. In particular, the accuracy of a balance design (ni = n, i = 1, 2, ..., k) for estimating p is compared with the accuracy of an unbalanced "natural" design, in which the ni are sampled at random from family size distributions that tend to occur in practice. It is found for two different estimators of p that the balanced design is usually preferable, but only to a small degree if the number of families sampled is greater than 50.