Real-time digital processing of blood pressure and heart rate data of tethered nonhuman primates.

To facilitate data analysis, we developed a computerized system for collecting and screening systolic, diastolic, and mean arterial blood pressure, and heart rate data. Each value is tested for acceptability (filtered), in real-time, by a computer algorithm. Level one, spike detection, is performed by independently comparing each datum to specified upper and lower limits. Level two, damping detection, is applied to data which passed level one and is categorized as mild, severe, or none. We monitored 69 tethered conscious baboons for approximately eight 12-hour overnight periods to obtain 23,433,000 one-second data points per variable. The computerized system eliminated approximately 65% of unacceptable data and highlighted problems, thus reducing the time required to inspect digital files or analog hard-copy recordings. No acceptable data were rejected by the filter and all data rejected by the filter also were unacceptable by data inspection.

A comparison of three indicators for identifying Mexican Americans in epidemiologic research. Methodological findings from the San Antonio Heart Study.

Because the issue of how to empirically identify Mexican Americans in health-related research is still unresolved, the authors compared the performance of three indicators for identifying Mexican Americans across five distinct population subgroups: men and women in two age strata, and residents in low, middle, and high socioeconomic neighborhoods. Individual surname had the lowest sensitivity, specificity, and predictive values in the pooled population sample and varied the most widely on these parameters across population subgroups. Parental surnames, which are available on vital statistics and could easily be added to other health records used in secondary analyses, offered a significant improvement over individual surname in classifying persons as Mexican American. The San Antonio Heart Study (SAHS) algorithm, a nine-item indicator which uses parental surnames, birthplace of both parents, self-declared ethnic identity, and ethnic background of grandparents, had the highest sensitivity, specificity, and predictive values and varied the least on these parameters across different sex, age, and socioeconomic status population subgroups. The performance of all indicators was lower at the higher socioeconomic status levels. The findings suggest that it may be useful to use parental surnames as an indicator for Mexican-American ethnicity in research involving vital statistics and to add parental surnames to other health records frequently used in secondary analyses. Since the SAHS algorithm can be adapted for use with non-Mexican origin Hispanic subgroups, it may be a useful indicator for Mexican-American (or other Hispanic) ethnicity in survey research.

Prevalence, detection, and control of hypertension in a biethnic community. The San Antonio Heart Study.

A survey was carried out on a random sample of 1,288 Mexican Americans and 929 Anglos living in three socially distinct neighborhoods in San Antonio, Texas. Hypertension was defined as diastolic blood pressure greater than or equal to 95 mmHg or currently taking antihypertensive medication. Overall age-adjusted prevalence rates of hypertension were similar for Mexican-American and Anglo men (10.0 and 9.8%, respectively); for women, the Mexican-American rate was slightly lower than that for Anglos (7.8 and 9.7%, respectively). After adjustment for obesity differences, Mexican Americans have a tendency toward lower hypertension rates than Anglos of the same socioeconomic level. Only among women was a decline in the prevalence of hypertension with increasing socioeconomic status observed. Mexican Americans have a higher proportion of newly diagnosed hypertension, and, among previously diagnosed cases, a lower proportion are on antihypertensive medication than Anglos. The rates of hypertension control found in this survey are among the highest reported in the United States at the community level. Despite this, Mexican Americans still lag somewhat behind Anglos of the same socioeconomic level in awareness, treatment, and degree of hypertension control, suggesting the possibility of sociocultural barriers to adequate medical care.

Socioeconomic status and the prevalence of clinical gallbladder disease.

The prevalence of clinical gallbladder disease was determined in a cross-sectional survey of Mexican Americans and non-Hispanic whites. The study population was randomly selected from three urban neighborhoods representing different socioeconomic strata. Gallbladder disease was defined as a history of cholecystectomy, or of stones on cholecystography. Mexican American women had an age-standardized prevalence of 16.9%, vs 8.7% for non-Hispanic whites (p less than 0.0001). Prevalences in men were 4.2 and 3.4%, respectively. The ethnic differences in women persisted after stratification by age, parity, and body mass index. Gallbladder disease prevalence was inversely related to four measures of socioeconomic status. After controlling for age, obesity, parity, and ethnicity, the prevalence in women was inversely related to levels of education, income, occupational status, and neighborhood. These socioeconomic differences, if not the result of detection bias, suggest that environmental factors may play a role in gallstone pathogenesis. Identification of such factors may lead to the development of preventive strategies.