American Samoan Research Articles

Changes in some health status characteristics of American Samoan men: Preliminary observations from a 12-year follow-up study.

One of the concomitants of the rapid socioeconomic and medical changes which occurred in American Samoa beginning with World War II has been an increase in chronic diseases, especially cardiovascular disease and diabetes. As part of the Samoan Studies Project, a 1976 survey focusing on obesity and blood pressure was conducted in American Samoa. A total of 624 men age 18 or greater were seen at that time. In 1989 we conducted a follow-up examination of 31 of these men, reassessing blood pressure, and also examining blood glucose and previously diagnosed health problems, focusing on chronic diseases such as hypertension, stroke, cancer, and diabetes. In a prospective analysis of mortality, Crews (Hum. Biol. 60:417-433, 1988) found that 111 American Samoan men who had blood pressures measured in a public health department survey in 1975 and subsequently died between 1975 and 1981, had higher average systolic and diastolic blood pressures than the 2,588 survivors (140/88 vs. 129/84). Using these data, the 1989 sample was stratified according to the 1976 blood pressure measurement of the men and a sample of 14 normotensive men (1976 blood pressure <140/90) and 17 hypertensives (1976 blood pressure ≥140/90) was selected. The average age, weight, and number of cigarettes smoked per day was not significantly different for these two groups at the 12-year follow-up. However, several indicators of health status did differ. The hypertensive group had significantly higher systolic and diastolic blood pressures (P ≤ 0.001). Additionally, the hypertensive group had higher random blood glucose values (P ≤ 0.005) and were significantly more likely to be hypertensive and/or have impaired glucose tolerance (P ≤ 0.001). Change in weight was predictive of change in blood pressure, but not of absolute value of blood pressure. This paper notes the importance of elevated blood pressure as a predictor of future chronic disease risk for Samoan men. © 1993 Wiley-Liss, Inc.

Historical demographic and epidemiological studies of aging in American Samoans.

American Samoan mortality records, from 1920 through 1988, and epidemiological survey data from 1976 are used to examine demographic definitions of the elderly in different time periods and to examine the association of body habitus and blood pressure with mortality among middle-aged and older Samoans. In the 1920s, the average Samoan lived 24 years, but over 50% of deaths occurred prior to age 15. In the 1980s the average Samoan lived about 54 years and 50% of deaths occurred after age 58. The common definition for matua (an elder or true old one) was 50 years in 1962, an age to which only 17% of the population lived in the 1920s; this value increased to 60-65 years by 1976, when 53% of the population survived to age 50 years and 34% to age 65 years. These data suggest that quantitative demographic factors may have constrained Samoan cultural definitions of matua i.e., "elderliness" during the 20th century. Among middleaged and older Samoans who died between 1976 and 1980, body weight, body mass index (BMI), and systolic and diastolic blood pressure were differentially associated with cause-specific mortality by age and sex. None of these risk factors was associated with mortality in older men, but BMI and systolic pressure were significanlty lower among middle-aged men who died. In contrast, all four risk factors were associated positively with mortality in middle-aged women, but in older women only systolic pressure was.

Estimation of energy expenditure in Western Samoa, American Samoa, and Honolulu by recall interviews and direct observation.

Reliable and accurate estimates of energy expenditure are a fundamental requirement for research on energy balance, energy flow, and other biocultural phenomena. Cross-validation of estimates derived from more than one time-allocation method can detect sources of bias and may lead to estimates which are more credible than those from activity recalls used alone. This paper compares 24-hour activity recalls and direct observations as methods of estimating the energy expenditure of 145 18-37-year-old Samoans residing in rural Western Samoa, American Samoa, and Honolulu. Daily energy expenditure was estimated on 2 workdays by activity recalls (n = 214) or by focal-individual observations (n = 91). Samoan men expend 2,900-3,400 kcal/day and women expend 2,250-2,650 kcal/day. Estimates of energy expenditure in the Western Samoa sample are comparable to other subsistence horticultural societies, while the American Samoan and Honolulu samples are comparable to other sedentary working populations. Group estimates from recall interviews are 100-400 kcal/day higher than from observations, although this is only a difference of 5-10%. Overestimation of energy expenditure is more evident at higher work intensities than for sedentary activities. The apparent exaggeration of strenuous activity in this, and other, studies indicates that without cross-validation, self-reported activity data may often be confounded by an unknown amount of subjective bias.

Selective migration as a bias in modernization studies: Premigration differences in morphology and blood pressure among 15-30 year-old American Samoans.

Premigration differences in anthorpometry and blood pressure are examined for evidence of selective migration for biological characteristics. We conducted a 5-years follows-up of the migration status of 99 American Samoans 15-30 years old who had been previously examined in 1981 and found that 33 had migrated. Analysis of covariance of the baseline anthorpometry and blood pressures of the nonmigrants (n = 58) and those who subsequently migrated (n = 29) indicates that selective migration does occur among young American Samoan adults. Migrants of both sexes tended to be younger and leaner and had significantly lower mean blood pressures than nonmigrants even before migration. Selective migration of lean individuals with lower blood pressures may contribute to the lower blood pressures of migrants from American Samoa living in Hawaii or to the heterogeneity in other Samoan populations. These results are one of the few examples of biological selectivity demonstrated to date and illustrate the dangers of assuming that the effects of selective migration are negligible in studies of migration and health.

Cause-specific mortality, life expectancy, and debilitation in aging polynesians.

Between 1950 and 1980 life expectancy among middle-aged American Samoan men increased 22%; among women it increased 36%. The largest proportional increase were observed after age 65% Men 29%, women 118%. This study examined whether increasing longevity health of older Samoans. Cause-specific mortality data were used to calculate multiple decrement life tables for American Samoa by decades for both sexes from 1950 to 1979. Changes in two life table parameters were examined: The probability of dying from, and the remaining life expectancy among persons who would eventually die from, pneumonia/influenza, infections, cancer, or cardiovascular disease (CVD) after birth and after age 45. Pneumonia and infections may indicate frailty or delibitration in older individuals. The probability of dying from a specific cause after a particular age reflects its relative importance for survivors to that age. Residual life expectancy indicates whether older individuals are succumbing at earlier ages or surviving longer the risks of death from specific causes. Trends in the probability of dying from, and life expectancy among those ultimately dying from, pneumonia and infections did not suggest improved survival of debilitated individuals. Rather, they indicated that older Samoans may have had greater average resistance to pneumonia and infections in later cohorts. How much this was related to improved medical care and availability was not clear from the available data. However, Samoans who died from CVD and cancer did not survive longer than their counterparts had in earlier decades. Thus, there was little opportunity for an increase in debilitation among aging Samoans due to the longer-term survival of the chronically ill.

Cornell medical index responses and mortality in a Polynesian population

The Cornell Medical Index (CMI) is a health questionnaire consisting of a somatic division, divided into 12 sections organized by organ systems, and a psychosocial division. It has been suggested that the CMI taps a dimension of the perception of illness before clinical measurements detect disease. However, this has not been confirmed in nonwestern populations. Our purpose was to determine if the CMI predicted 6-year mortality in a Polynesian population. In 1975, 461 American Samoan men responded to the CMI. Thirty-one died between 1976 and 1981, 13 of cardiovascular disease (CVD). A logistic model was used to predict both total and CVD mortality during the follow-up period. Positive responses to the total, somatic, and psychosocial divisions of the CMI did not significantly improve prediction of mortality compared to models using only age. An analysis using section scores showed that several somatic sections were associated with CVD mortality, but none were associated with total mortality. This study suggests that the CMI is not a strong predictor of mortality and, by extension, of existing health status in American Samoa. Even if the CMI does measure the perception of illness, one cannot assume a priori that it is valid in any given anthropological population. Rather, the instrument must be pretested in each particular cultural setting.

Patterns of growth in weight and length among American Samoan infants

Well baby clinic records on 1, 186 infants born in 1975 to 1976 on the island of Tutuila, American Samoa, form the basis for this study of the growth in weight and length from birth to 12 months. Semi‐longitudinal curves of weight and length indicate that these infants have median weights near the NCHS 75th percentile (boys) and 90th percentile (girls) up to 6 months, falling to just below the 75th percentile by 12 months. Median lengths are between the NCHS 50th and 25th percentile. Weight gain from birth to six months was found to be higher than for any other reported population (4.92 kg, sexes combined). The infant feeding pattern was found to exert a significant influence on rate of weight gain for boys between birth and 1–4 months, with the breast‐fed boys gaining more rapidly than artificial‐fed infants.

Mortality related to cardiovascular disease and diabetes mellitus in a modernizing population

Excessive adiposity is associated with elevated rates of middle-aged mortality, particularly that related to cardiovascular disease (CVD) and diabetes mellitus (DM). One purpose of this study was to determine whether the population of American Samoa demonstrated the expected elevation of mortality rates related to these two causes. Accordingly for all American Samoan death records ( N = 1588) during the period 1962–74, both crude and age-standardized rates were calculated and interpopulation comparisons of DM and CVD were made. The second purpose of this research was to determine if elevated CVD mortality was associated with the islands' recent trend toward modernization. For this purpose 902 deaths of persons aged 30 or more were analyzed to determine change in CVD mortality over time and differences by degree of participation in modern life. The CVD-related mortality rate for Samoa was 82.1 per 100,000, compared to 368.6 reported for the United States in 1962. After age standardization the Samoan rate increased to 242.5, still below that of the United States. The Samoan DM-related mortality rate was 13.9 per 100,000, compared to a United States rate of 15.9 in 1959. After age adjustment, the respective rates were 32.2 and 13.4 (1957–59), the Samoan rate being more than double that the United States. Female CVD mortality in Samoa increased from 196.2 in the period 1963–66 to 363.0 in 1971–74, while male rates remained essentially unchanged (417.3 and 429.0 respectively). CVD mortality among males living in more modernized areas of the islands was 46.5% higher than that for male residents of more traditional areas (343.5 and 234.5 respectively); among females, however, the rate was highest for those living in traditional areas (398.7). CVD mortality for males classified to the ‘sedentary’ occupational category was 50% greater than that for males in the ‘active’.

Differential gain rates in intensive ESL programs: Who gains the most?

Students entering intensive English as a second language programs at various proficiency levels may make comparatively greater or lesser gains in proficiency over the same period of training. Whether or not some groups within a heterogenous student population can be expected to make significantly more rapid gains than others is the question addressed by this paper.’ Also tested is the assumption that scores on a standardized proficiency test can serve to identify individuals as likely to make greater or lesser gains. The problem of predicting differential gain rates is of particular interest to those involved in the intensive ESL program at New Mexico State University. Many students admitted to the program have had little or no preparation in English language skills, yet they are expected to be ready for graduate level work at the University after one year of language instruction. Our teaching strategies and program organization are therefore crucial to their academic success. It is hoped that a systematic analysis of relative gain would indicate if the prograrr is benefiting some types of students more than others. Significant biases, if found, would indicate the need for a thorough examination of program organization; possibly admissions policy would need to be examined if program goals were found unrealistic for all students currently being admitted. Numerous studies have examined the general problem of predicting success in language programs. Some have focused on individual characteristics of the learner (Carroll 1962), others with environmental variables of the classroom and school (Fatham 1976). Initial scores on an English proficiency test were analyzed by Mason (1971) who found them of no value in predicting the academic success or failure of international students at the University of Hawaii. Moran and Erion (1978) on the other hand found that initial scores on the Comprehensive English Language Test were significantly reliable predictors of academic success of American Samoan ESL speakers at the junior college level. Few studies have specifically observed the effect of an already attained proficiency level on further proficiency gains. Nevo, Sim and Bensousan (1977) examined 322 Israeli students in a non-intensive EFL reading course at Haifa University and found that generally students with higher entering scores on a proficiency test made greater gains on the same test a year later than did students with lower initial scores. The authors thus sum up their findings: “The rich get richer and the poor stay poor”. Similar results were obtained among tenth year English language students in a Swedish university (Marton 1972). However, until now no data has been available from intensive programs operating in the target language setting. The question remains, then, how adult L2 learners living in

Acculturation and Educational Achievement in American Samoan Adolescents

The relationship of educational achievement to overt (the directly observable) and covert (the psychological) measures of acculturation was explored for 190 high school seniors from American Samoa using canonical variate analysis. Three statistically significant and situationally interpretable relationships were found to exist between the overt and covert sets of variables, indicating that multiple acculturative approaches were operating simultaneously within Samoan adolescent culture. Educational achievement was found to be related mainly to the modern man approach to acculturation, the only approach to cross-validate. The study emphasized the probable multivariate nature of the acculturation process and the importance of verifying hypotheses through cross-validation.

ON THE ETHOLOGICAL DIFFERENTIATION OF DROSOPHILA ANANASSAE AND DROSOPHILA PALLIDOSA IN SAMOA.

A number of significant studies of genetic divergence and speciation in island populations of Drosophila have been undertaken in recent years. Certainly the grandest example of this has been the detailed study of the spectacular array of Drosophila species native to the Hawaiian Islands begun under the leadership of the late Professor Wilson S. Stone of the University of Texas and Professor D. Elmo Hardy of the University of Hawaii, and still being carried on by Hardy and a number of their colleagues; e.g., see Carson et al. (1970). Other island groups and Drosophila species have also been investigated by Stone and others at the University of Texas. Among these studies are those on Drosophila ananassae populations from island groups in the central and western Pacific Ocean, including light (brownish-yellow) and dark (blackish-brown) D. ananassae-like populations found on the American Samoan island of Tutuila. These populations are especially interesting in that, aside from the pigmentation difference, they are morphologically nearly indistinguishable and, in spite of exhibiting no apparent postmating reproductive barriers (Stone et al., 1966), they coexist together on this island as separate, reproductively isolated units. That they are sexually isolated has been shown cytologically (Futch, 1966) and ethologically (Futch, 1966; Spieth, 1966) with strains from Pago Pago, Tutuila. In recent years other collections of similar light and dark D. ananassae-like flies have been obtained from other islands in the Samoan archipelago as well as from islands in the Fijian group. Based mainly on the cytological and ethological evidence cited above concerning the genetic isolation of these light and dark forms, Bock and Wheeler (1972) recognize the two as distinct species belonging to the D. ananassae subgroup of the D. melanogaster species group of Drosophila. The dark flies have been identified as Drosophila ananassae Doleschall, a polytypic, widespread (circumtropical) domestic species of the tropical and sub-tropical world, whereas they describe the light flies as Drosophila pallidosa. This recently described species has a relatively localized distribution presently known only to include the southcentral Pacific islands of Samoa and Fiji where it exists side-by-side with its widely distributed sibling, D. ananassae. That two such very closely related, potentially interfertile sympatric species have been found living together successfully and separately in the island groups of Samoa and Fiji seems to warrant further investigation. As a part of this continuing investigation, populations from other islands of the Samoan group have been analyzed cytologically and for crossing fertility as stocks have become available to me.

Hyperuricemia in American Samoans.

AbstractThe mean serum uric acid of 71 normal adult American Samoan men was 6.8 mg%. Serum cholesterol, electrolytes, creatinine and total protein measurements were in the usual normal range and none correlated well with the serum urate. Like other Polynesian people, gout, obesity, diabetes and ischemic heart disease seem to be common among Samoans.

A New Map of the American Samoan Islands: Further Comment

A New Map of the American Samoan Islands: Further Comment

A New Map of the American Samoan Islands

A New Map of the American Samoan Islands