Influência da cafeína no comportamento da pressäo arterial e da agregaçäo plaquetária / Influence of caffeine on blood pressure and platelet aggregation

OBJECTIVE: Studies have demonstrated that methylxanthines, such as caffeine, are A1 and A2 adenosine receptor antagonists found in the brain, heart, lungs, peripheral vessels, and platelets. Considering the high consumption of products with caffeine in their composition, in Brazil and throughout the rest of the world, the authors proposed to observe the effects of this substance on blood pressure and platelet aggregation. METHODS: Thirteen young adults, ranging from 21 to 27 years of age, participated in this study. Each individual took 750mg/day of caffeine (250mg tid), over a period of seven days. The effects on blood pressure were analyzed through the pressor test with handgrip, and platelet aggregation was analyzed using adenosine diphosphate, collagen, and adrenaline. RESULTS: Diastolic pressure showed a significant increase 24 hours after the first intake (p<0.05). This effect, however, disappeared in the subsequent days. The platelet aggregation tests did not reveal statistically significant alterations, at any time during the study. CONCLUSION: The data suggest that caffeine increases diastolic blood pressure at the beginning of caffeine intake. This hypertensive effect disappears with chronic use. The absence of alterations in platelet aggregation indicates the need for larger randomized studies.

Prevalência e aspectos sócio-culturais e econômicos da hipertensão arterial em centro de saúde da zona norte de Manaus / Prevalence and sociocultural and economic aspects of hypertension in a health center of the northern area of Manaus

PURPOSE: To verify the prevalence and the possible sociocultural and economic factors involved in high blood pressure (HBP), intending to contribute to the elaboration of public health programs. METHODS: The blood pressure of 1,766 individuals, aging 13 years old or more, was measured by the auscultatory method, using a stethoscope and a sfigmomanometer. It was included in the HBP group, the individual presenting blood pressure above 140 x 90 mmHg in two measurements on different occasions. These individuals answered a form searching for sociocultural and economic aspects. RESULTS: Among the individuals examined, 76 were considered to have HBP. There was an increase on the prevalence of HBP with an increase of age, being the greatest among the individuals aging 49 years or more. It was observed significant association between age and HBP (p < 0.05), but the same did not happen with sex or skin color. In most part of the individuals with HBP, it was observed low family income and low educational level. Half of the HBP patients were used to eat with salt and fat. CONCLUSION: The educational level, economic status, and sociocultural habits of a person constitute factors that must be considered in the development of public health programs for control and reduction of the prevalence of HBP

Objetivo - Verificar a prevalência e os possíveis fatores socioculturais e econômicos envolvidos na hipertensão arterial (HA), visando contribuir para a elaboração de programas em nível de saúde pública. Métodos - Foi aferida a pressão arterial (PA) de 1.766 indivíduos, a partir dos 13 anos de idade, pelo método auscultatório, utilizando-se estetoscópio e esfigmomanômetro e considerando-se hipertensos aqueles com valores >140x90mmHg, em duas aferições, em ocasiões diferentes. Nestes foi aplicado questionário abordando aspectos socioculturais e econômicos. Resultados - No estudo, 76 indivíduos foram considerados hipertensos. A prevalência da HA aumentou com o aumento da idade, sendo maior a partir dos 49 anos (19,5%). Foi observada associação significativa entre idade e HA (p<0,05), o mesmo não ocorrendo com sexo ou cor: Na maioria dos hipertensos, observaram se baixa renda familiar e menor grau de instrução. Dieta rica em gordura e sal, esteve presente em 50% dos hipertensos. Conclusão - O grau de instrução, a condição econômica e os hábitos socioculturais do indivíduo são fatores que devem ser considerados para a elaboração de programas em nível de saúde pública, visando o controle e a redução da HA