Relationship between skin color and blood pressure in egyptian adults: results from the national hypertension project

Sex differences in hypertension incidence and risk factors: a population-based cohort study in Southern Iran

BACKGROUND

Hypertension (HTN) is a major global public health concern. This study aims to identify gender differences to inform more effective prevention strategies and targeted management approaches.

METHODS

This prospective cohort study included 7,710 participants aged 40 to 70 years, with a mean follow-up duration of 5.2 years. HTN was defined using European hypertension management guidelines. A Cox regression model was employed to determine factors associated with HTN, adjusting for confounding variables effects.

RESULTS

During the mean follow-up period of 5.2 years, the incidence rate of hypertension was 21.54 per 1,000 person-years, with females exhibiting a higher incidence than males. Several significant predictors of HTN were identified. In men, key risk factors included age (60-70 years, 2.83-fold increase, 95% CI 2.05-3.92), high waist-to-height ratio (5.63-fold increase, 95% CI 2.42-13.07), smoking (2.68-fold increase, 95% CI 1.04-6.91), and opium use (1.93-fold increase, 95% CI 1.06-3.49). In women, significant predictors included age (60-70 years, 3.65-fold increase, 95% CI 2.59-5.15), contraceptive drug use (1.24-fold increase, 95% CI 1.01-1.52), high waist-to-height ratio (1.87-fold increase, 95% CI 1.19-2.92), pre-HTN (3.64-fold increase, 95% CI 3.01-4.40), and kidney stones (1.32-fold increase, 95% CI 1.06-1.65).

CONCLUSION

This study identified key predictors of hypertension (HTN) with notable gender differences. For men, significant risk factors included age, high waist-to-height ratio, smoking, and opium use; for women, the prominent predictors were age, contraceptive use, pre-HTN, and kidney stones. These findings highlight the need for gender-specific strategies in HTN prevention and management, focusing on modifiable risk factors by gender.

Melanin-based plumage coloration and melanin content in organs in the barn owl

Although the evolutionary ecology of melanin pigments and melanin-based coloration has been studied in great details, particularly in birds, little is known about the function of melanin stored inside the body. In the barn owl Tyto alba, in which individuals vary in the degree of reddish pheomelanin-based coloration and in the size of black eumelanic feather spots, we measured the concentration in melanin pigments in seven organs. The eyes had by far the most melanin then the skin, pectoral muscle, heart, liver, trachea, and uropygial gland. The concentration in eumelanin was not necessarily correlated with the concentration in pheomelanin suggesting that their production can be regulated independently from each other. Redder barn owls had more pheomelanin in the skin and uropygial gland than white owls, while owls displaying larger black feather spots had more eumelanin in the skin than small-spotted owls. More data are required to evaluate whether melanin-based traits can evolve as an indirect response to selection exerted on melanin deposition in organs.

Validity of self‐reported skin color by using skin color evaluation scale

INTRODUCTION

Although skin color has been suggested to be associated with the risk of some chronic disease, there has been no validated visual skin-color scale, with which subjects can self-report their skin color. Our objective was to develop a visual skin color evaluation scale for self-reporting that would be useful in large-scale epidemiological studies.

MATERIALS AND METHODS

Study participants were 99 university Japanese students aged 19-29. We developed a skin color evaluation scale consisting of six colors from light to dark. Participants were asked to choose one color that was the closest to their skin color. Their skin color was measured on the back of the hand and the inner upper arm by an examiner using a narrowband reflective spectrophotometer. Self-reported skin color was compared with the melanin and erythema indices.

RESULTS

Spearman's rank correlation coefficients of self-reported color with the melanin index after adjusted for age, temperature, and humidity were moderate but significant at both sites for both men and women. The correlation coefficients with the erythema index were significant only on the back of the hand for men. The higher melanin index was significantly associated with the darker skin color in both sexes for both sites. The erythema index showed such a significant trend only in men and not in women.

CONCLUSIONS

The validity of the skin color chart was moderate of melanin among Japanese people. It may be useful for large population studies examining the relationships between skin color and health outcomes.

Frequency and risk factors of carotid artery disease among ischemic stroke patients in the south Egypt: hospital-based study

Background

Limited data are available on the frequency of carotid artery disease among cerebrovascular ischemic stroke (CVS) patients in south Egypt. The aim of the present study is to determine the prevalence and risk factors of extracranial atherosclerosis among stroke patients using extracranial duplex ultrasound.

Results

142 patients (76.8%) were males and 43 (23.2%) were females. Their mean age was 63.3 ± 9.79 years with no significant difference between the mean age of the male and female groups. NIHSS score ranged from 3 to 25 (mean ± S.D; 11.89 ± 4.91). 66 patients (35.7%) had no atherosclerotic changes, 75 patient (40.5%) had stenosis < 70% and 44 patients (23.8%) had stenosis ≥ 70%. The most prevalent modifiable risk factors for atherosclerosis were hypertension (74.8%), hyperlipidemia (70.6%), smoking (59.7%) and DM (45.4%).

Conclusion

Atherosclerosis among people in the south Egypt is relatively high in comparison to other regions in Egypt and Middle East. This is a call for performing further population-based epidemiological studies, to address the exact magnitude of the problem and invest into prevention.

Prediction of Hypertension Based on Facial Complexion

This study aims to investigate the association between hypertension and facial complexion and determine whether facial complexion is a predictor for hypertension. Using the Commission internationale de l'éclairage L*a*b* (CIELAB) color space, the facial complexion variables of 1099 subjects were extracted in three regions (forehead, cheek, and nose) and the total face. Logistic regression was performed to analyze the association between hypertension and individual color variables. Four variable selection methods were also used to assess the association between hypertension and combined complexion variables and to compare the predictive powers of the models. The a* (green-red) complexion variables were identified as strong predictors in all facial regions in the crude analysis for both genders. However, this association in men disappeared, and L* (lightness) variables in women became the strongest predictors after adjusting for age and body mass index. Among the four prediction models based on combined complexion variables, the Bayesian approach obtained the best predictive in men. In women, models using three different methods but not the stepwise Akaike information criterion (AIC) obtained similar AUC values between 0.82 and 0.83. The use of combined facial complexion variables slightly improved the predictive power of hypertension in all four of the models compared with the use of individual variables.

Differentials in risk factors for chronic non-communicable diseases from the race/color standpoint

This article aims to analyze the differences between the prevalence of risk factors of non-communicable chronic disease by race/color. It is a cross-sectional study using data from a telephone survey of 45,448 adults. Prevalence ratios for chronic disease risk factors by race/color were calculated. After adjustments were made for education and income, race/color differences persisted. Among afro-descendant and mulatto women and mulatto men a higher prevalence ratio was identified of physical activity at work and physical activity at home. Afro-descendant women and mulatto men indulged in less physical inactivity. Mulatto men and women showed a lower prevalence of smoking and consumption of 20 cigarettes daily and lower consumption of fruit and vegetables. A higher consumption of full-fat milk with and beans was observed among afro-descendant and mulatto men. Afro-descendant women had a lower prevalence of drinking and driving. Afro-descendant women and men ate more meat with fat and afro-descendant men suffered more from hypertension. Differences in risk factors by race/color can be explained by cultural aspects, by not fully adjustable socioeconomic differences that determine less access to goods and less opportunities for the afro-descendant population.

Increased vitamin D and calcium intake associated with reduced mammographic breast density among premenopausal women

Vitamin D has been identified as a weak protective factor for postmenopausal breast cancer (relative risk, ~0.9), whereas high breast density has been identified as a strong risk factor (relative risk, ~4-6). To test the hypothesis that there is an association between vitamin D intake, but not circulating vitamin D levels, and mammographic breast density among women in our study, we conducted a cross-sectional study of 165 screening mammography patients at Nashville General Hospital's Breast Health Center, a public facility serving medically indigent and underserved women. Dietary and total (dietary plus supplements) vitamin D and calcium intakes were estimated by the Harvard African American Food Frequency Questionnaire, and blood samples were analyzed for 25-hydroxyvitamin D. Average percent breast density for the left and right breasts combined was estimated from digitized films using an interactive thresholding method available through Cumulus software. After statistical adjustment for age, race, and body mass index, the results revealed that there were significant trends of decreasing breast density with increasing vitamin D and calcium intake among premenopausal but not among postmenopausal women. There was no association between serum vitamin D and breast density in premenopausal or postmenopausal women. Confirmation of our findings in larger studies may assist in clarifying the role of vitamin D in breast density.

Sodium-to-potassium ratio and blood pressure, hypertension, and related factors

The potential cost-effectiveness and feasibility of dietary interventions aimed at reducing hypertension risk are of considerable interest and significance in public health. In particular, the effectiveness of restricted sodium or increased potassium intake on mitigating hypertension risk has been demonstrated in clinical and observational research. The role that modified sodium or potassium intake plays in influencing the renin-angiotensin system, arterial stiffness, and endothelial dysfunction remains of interest in current research. Up to the present date, no known systematic review has examined whether the sodium-to-potassium ratio or either sodium or potassium alone is more strongly associated with blood pressure and related factors, including the renin-angiotensin system, arterial stiffness, the augmentation index, and endothelial dysfunction, in humans. This article presents a systematic review and synthesis of the randomized controlled trials and observational research related to this issue. The main findings show that, among the randomized controlled trials reviewed, the sodium-to-potassium ratio appears to be more strongly associated with blood pressure outcomes than either sodium or potassium alone in hypertensive adult populations. Recent data from the observational studies reviewed provide additional support for the sodium-to-potassium ratio as a superior metric to either sodium or potassium alone in the evaluation of blood pressure outcomes and incident hypertension. It remains unclear whether this is true in normotensive populations and in children and for related outcomes including the renin-angiotensin system, arterial stiffness, the augmentation index, and endothelial dysfunction. Future study in these populations is warranted.

Hypertension in developing countries

Data from different national and regional surveys show that hypertension is common in developing countries, particularly in urban areas, and that rates of awareness, treatment, and control are low. Several hypertension risk factors seem to be more common in developing countries than in developed regions. Findings from serial surveys show an increasing prevalence of hypertension in developing countries, possibly caused by urbanisation, ageing of population, changes to dietary habits, and social stress. High illiteracy rates, poor access to health facilities, bad dietary habits, poverty, and high costs of drugs contribute to poor blood pressure control. The health system in many developing countries is inadequate because of low funds, poor infrastructure, and inexperience. Priority is given to acute disorders, child and maternal health care, and control of communicable diseases. Governments, together with medical societies and non-governmental organisations, should support and promote preventive programmes aiming to increase public awareness, educate physicians, and reduce salt intake. Regulations for the food industry and the production and availability of generic drugs should be reinforced.

The "Got D'ViBE?" study: an inter-institutional project assessing vitamin D and mammographic breast density

A multi-institutional collaboration was forged to implement a study of the relationship between Vitamin D and breast density among medically underserved women. This effort resulted in techniques to measure vitamin D levels, breast density, and sunlight exposure. Outcomes from this collaboration may provide insight to researchers conducting similar investigations.

Skin color, social classification, and blood pressure in southeastern Puerto Rico

OBJECTIVES

We tested competing hypotheses for the skin color-blood pressure relationship by analyzing the association between blood pressure and 2 skin color variables: skin pigmentation and social classification.

METHODS

We measured skin pigmentation by reflectance spectrophotometry and social classification by linking respondents to ethnographic data on the cultural model of "color" in southeastern Puerto Rico. We used multiple regression analysis to test the associations between these variables and blood pressure in a community-based sample of Puerto Rican adults aged 25-55 years (n=100). Regression models included age, gender, body mass index (BMI), self-reported use of antihypertensive medication, and socioeconomic status (SES).

RESULTS

Social classification, but not skin pigmentation, is associated with systolic and diastolic blood pressure through a statistical interaction with SES, independent of age, gender, BMI, self-reported use of antihypertensive medication, and skin reflectance.

CONCLUSION

Our findings suggest that sociocultural processes mediate the relationship between skin color and blood pressure. They also help to clarify the meaning and measurement of skin color and "race" as social variables in health research.

Skin pigmentation, self-perceived color, and arterial blood pressure in Puerto Rico

Darker skin color has been associated with higher average blood pressure in several African-derived populations in the Americas. This pattern has been interpreted as evidence of genetic, physiologic, or sociocultural mechanisms, but existing evidence does not provide an adequate means of evaluating these alternatives. This paper introduces a measurement strategy to isolate the cultural and biological dimensions of skin color, and it develops a specific hypothesis regarding the cultural significance of skin color in Puerto Rico and its relationship to arterial blood pressure. Data come from a face-to-face survey in southeastern Puerto Rico (N = 100). There is no association between blood pressure and skin pigmentation, as measured by reflectance spectrophotometry. However, the discrepancy between self-perceived color and skin pigmentation, a measure we call "color incongruity," is associated with systolic blood pressure (SBP) through an interaction with socioeconomic status (SES) (P = 0.009). For low-SES respondents, darker self-ratings of color relative to skin pigmentation are associated with higher mean SBP. For high-SES respondents, however, darker self-ratings of color relative to pigmentation are associated with lower mean SBP. We interpret this pattern as evidence that the relationship between skin color and blood pressure is mediated by sociocultural processes, and we highlight the need for testable hypotheses and appropriate measurement operations in research on racial inequalities in health.

Non-invasive measurements of skin pigmentation in situ

Objective in situ measurements of skin pigmentation are needed for accurate documentation of pigmentation disorders, in studies of constitutive and induced skin pigmentation, for testing of the efficacy of pro-pigmentation or de-pigmentation agents, etc. Non-invasive instrumental measurements of skin pigmentation have been used for many decades. All are based on the ability of melanin to attenuate light. However, hemoglobin in dermal capillaries also attenuates light and needs to be accounted for when pigmentation is assessed. The methods under consideration include: (a) single point measurements, in which light reflected from a defined skin area is collected and a pigment index is calculated representing the average pigmentation over the examined area, and (b) imaging methods that attempt to generate a concentration distribution map of melanin pigment for the skin area being imaged. In this article, we describe the potentials and the limitations of the different approaches to both single point and imaging methods.