A comparison of cardiovascular reactivity of rural blacks, urban blacks and whites

Incidence of psycho-social well-being in a rural community of South Africa

This article explores the incidence of psychosocial well-being within Lokaleng; a rural community located in the North West province of South Africa. While the community is unique, it shares similarities with many other rural communities in South Africa, such as being deprived of various resources and being impoverished, indicating a need to explore the incidence of psychosocial well-being in this community as there has been no research on this phenomenon in this community specifically. A quantitative, cross-sectional design was employed. A purposive sample of adult community members (n = 189) completed a battery of validated questionnaires and data were analyzed with the IBM SPSS Statistics 26 software package. The results are indicative that the sample experienced lower levels of psychosocial well-being, which supports similar findings of other South African studies that rural communities tend to report lower levels of psychosocial well-being.

Acculturation to Western society as a risk factor for high blood pressure: a meta-analytic review

OBJECTIVE

A number of studies have documented that acculturation to western society is related to an increase in blood pressure (BP). Although there is evidence that higher socioeconomic status appears related to better cardiovascular health, increasing acculturation to western society appears related to worse cardiovascular health. The purpose of this meta-analysis was to investigate the association between acculturation and BP.

METHODS

Literature searches yielded 125 relevant research manuscripts, which were coded by teams of two independent raters. This study was conducted in 2003 and 2004, and research databases such as MEDLINE and PsychINFO were searched through 2004. Measures of association (effect sizes) were extracted for both systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings. Random effects models were used to analyze the resulting data.

RESULTS

The overall effect sizes associated with acculturation were 0.28 for SBP and 0.30 for DBP, with increasing acculturation to western society related to higher BP. More acculturated individuals had an average of 4 mm Hg higher BP than less acculturated individuals, which is similar to the effect sizes of known risk factors for high BP such as diet and physical activity. The effects of acculturation on BP appear to be universal, with similar effect sizes found across all regions of the world. Change in BP due to acculturation was not related to body mass index (BMI) or cholesterol but was related to length of residence in the new culture, with the largest effect sizes seen on initial entry and then decreasing rapidly within the first few years. Sudden cultural changes, such as migration from rural to urban settings, resulted in the largest effect sizes, which finding supports the hypothesis that the stress of cultural change is important role in the acculturation effect.

CONCLUSIONS

Acculturation to western society is associated with higher BP, and the distress associated with cultural change appears to be more influential than changes in diet or physical activity. Future studies would benefit from investigating how cultural change affects health and examining whether some non-Western cultural values and practices are health protective.

Prolactin, testosterone and cortisol as possible markers of changes in cardiovascular function associated with urbanization

People living in large informal settlements in South Africa showed a significant increase in cardio/cerebrovascular disease. This study was undertaken to compare the cardiovascular and endocrine parameters of urbanized and rural black female and males. The hormone levels such as prolactin, cortisol and testosterone may also change with urbanization and could make a contribution to the high rate of hypertension. For this study, 1202 black subjects were selected from 37 randomly selected rural and urbanized settlements. Resting blood pressure was recorded with a Finapres apparatus. Cardiac output, stroke volume, heart rate, total peripheral vascular resistance and compliance had been obtained with the Fast Modelflow software program. An acute laboratory stressor (hand dynamometer exercise) was applied to challenge the cardiovascular system and the measurements were repeated. Blood sampling was done and hormone levels were determined by biochemical analyses. For females, significant lower levels of cortisol were found in the urban strata in comparison with the rural strata. The testosterone levels were significantly lower and the prolactin levels significantly higher for females in the informal settlements compared with the rural strata. It is noticeable that most cardiovascular parameters showed the highest changes with the application of the stressor in the informal settlement strata and the lowest in people living on farms for both male and female. The prolactin levels in males are significantly higher in the informal settlement stratum. Subjects living in informal settlements showed a noticeable endocrine pattern of ongoing stress that can be associated with changes in the cardiovascular parameters with urbanization. This can partly explain the reported high rate of cardio/cerbrovascular disease in black South Africans living in informal settlements.

Cardiovascular reactivity patterns elicited by the cold pressor test as a function of aging

BACKGROUND AND AIMS

The cold pressor test has been widely used in previous cardiovascular reactivity studies as a predictor of hypertension. However, the influence of the physical adaptations of the arterial wall with increasing age on reactivity has not been delineated.

METHODS

64 men divided into 5 different age groups participated in a laboratory protocol consisting of submerging one hand in ice water for one minute while changes in blood pressure were continuously measured.

RESULTS

The results indicated that with increasing age, the systolic blood pressure change, especially the rate of change (slope) is more pronounced than changes in diastolic blood pressure.

CONCLUSIONS

With increasing age, there is a shift from a diastolic blood pressure reactivity pattern to a more systolic blood pressure reactivity pattern during application of the cold pressor test. This could be ascribed to a decrease in arterial compliance.