Melissa Maritz - Academia.edu (original) (raw)

Papers by Melissa Maritz

Diabetes Research and Clinical Practice

Black populations from sub-Saharan Africa have a high prevalence of cardiovascular disease, which... more Black populations from sub-Saharan Africa have a high prevalence of cardiovascular disease, which places significant strain on public health systems. Aortic stiffness is a prominent risk factor for cardiovascular disease development. We reported earlier that excessive alcohol use predicts aortic stiffness. However, we require a better understanding of other biomarkers involved in stiffness development, beyond alcohol use. Therefore, we determined which biomarkers (metabolic, inflammatory, endothelial activation and oxidative stress) relate to aortic stiffness in young and older black South Africans, self-reporting no alcohol-use. Methods: We included cross-sectional data from young (aged 24.7 ± 3.24 years) black adults participating in the African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension (African-PREDICT) study (N=216), and fiveyear follow-up data from older (aged 61.6 ± 9.77 years) black adults (N=322) participating in the South African leg of the Prospective Urban and Rural Epidemiology study, conducted in the North West Province (PURE-SA-NWP). We excluded all participants self-reporting alcohol use. We determined biomarkers from blood samples, and measured carotid-femoral pulse wave velocity (PWV). Results: Of all biomarkers investigated in multivariable-adjusted regression analyses, only plasma glucose (R 2 =0.24, β=0.21, p<0.001) and glycated haemoglobin (R 2 =0.22, β=0.17, p=0.002) independently predicted PWV five years later in older adults. We found no other associations in young or older black adults. Conclusion: Dysglycaemia independently predicted aortic stiffness after five years in older black adults. Life-course management of body weight and sugar intake are important in preventing early vascular ageing and subsequent cardiovascular disease development in Africa.

Parents, Gerrit and Angelique, thank you for your love, support, understanding and helpfulness th... more Parents, Gerrit and Angelique, thank you for your love, support, understanding and helpfulness throughout this year. Thank you to Maretha Botes for the language editing of this dissertation.

Increased arterial stiffness is linked to cardiovascular disease development, particularly in bla... more Increased arterial stiffness is linked to cardiovascular disease development, particularly in black populations. Since detrimental health behaviors in young adults may affect arterial stiffness, we determined whether arterial stiffness associates with specific health behaviors, and whether it is more pronounced in young healthy black compared to white adults. We included 373 participants (49% black, 42% men) aged 20–30 years. Mean arterial pressure was higher for blacks than whites (P < .001), but carotid-femoral pulse wave velocity was similar (6.37 vs. 6.36 m/s; P 1⁄4 .89) after adjustment for mean arterial pressure. The black group had higher gamma-glutamyltransferase (GGT) (P < .001), cotinine, reactive oxygen species, interleukin-6, and monocyte-chemoattractant protein-1 (all P .017). Pulse wave velocity related positively and independently to GGT in both groups before and after multiple adjustments (both b 1⁄4 0.15; P .049). Blacks had an unfavorable vascular profile and...

Journal of the American Society of Hypertension : JASH, Jan 4, 2016

Increased arterial stiffness is linked to cardiovascular disease development, particularly in bla... more Increased arterial stiffness is linked to cardiovascular disease development, particularly in black populations. Since detrimental health behaviors in young adults may affect arterial stiffness, we determined whether arterial stiffness associates with specific health behaviors, and whether it is more pronounced in young healthy black compared to white adults. We included 373 participants (49% black, 42% men) aged 20-30 years. Mean arterial pressure was higher for blacks than whites (P < .001), but carotid-femoral pulse wave velocity was similar (6.37 vs. 6.36 m/s; P = .89) after adjustment for mean arterial pressure. The black group had higher gamma-glutamyltransferase (GGT) (P < .001), cotinine, reactive oxygen species, interleukin-6, and monocyte-chemoattractant protein-1 (all P ≤ .017). Pulse wave velocity related positively and independently to GGT in both groups before and after multiple adjustments (both β = 0.15; P ≤ .049). Blacks had an unfavorable vascular profile and...

Journal of Hypertension, 2017

Objective: Black populations exhibit higher arterial stiffness than whites and suffer a dispropor... more Objective: Black populations exhibit higher arterial stiffness than whites and suffer a disproportionate burden of cardiovascular disease. It is therefore important to identify modifiable health behaviours predicting large artery stiffness in blacks. We examined whether traditional cardiovascular risk factors and health behaviours of black South Africans predict large artery stiffness 10 years later. Methods: We included 650 HIV-free participants (32.8% men) and collected data in rural and urban areas of the North West Province in 2005 and 2015. We collected questionnaire data, anthropometry, blood pressure and determined cardiometabolic and inflammatory markers from blood samples. We measured carotid-femoral pulse wave velocity (PWV) at follow-up. Results: A total of 25.3% of our population, aged 65 AE 9.57 years, had a PWV exceeding 10 m/s. In multivariable-adjusted regression analyses, the strongest predictors of PWV were mean arterial pressure, age and heart rate (all P < 0.024). Urban locality (R 2 ¼ 0.31, b ¼ 0.12, P ¼ 0.001), self-reported alcohol use (b ¼ 0.11, P ¼ 0.018) and plasma glucose (b ¼ 0.08 P ¼ 0.023) associated positively with PWV at follow-up. We found a negative association between PWV and BMI (b ¼ À0.15, P ¼ 0.001), and no associations with sex, smoking, inflammatory markers, lipids, liver enzymes or antihypertensive medication. When replacing self-reported alcohol with gamma-glutamyltransferase, the latter associated positively with PWV (b ¼ 0.09, P ¼ 0.023). Conclusion: A health profile associated with excessive alcohol use, including an urban setting, elevated plasma glucose and lower BMI predicts large artery stiffness independently of age and blood pressure in black South Africans over 10 years. This observation prompts urgent public health strategies to target alcohol overuse.

Cardiovascular Journal of Africa

Introduction: An important feature of hypertension is a reduction in large artery distensibility,... more Introduction: An important feature of hypertension is a reduction in large artery distensibility, which may be due to structural and functional adaptations. Black populations are particularly prone to the development of hypertension. We therefore compared the carotid characteristics between fiveyear sustained hypertensive and normotensive black South Africans, and investigated how carotid characteristics relate to cardiometabolic risk factors, inflammation, endothelial activation and health behaviours. Methods: We included HIV-free black South Africans who were either consistently hypertensive (n = 351) or normotensive (n = 241) from 2005 to 2010. We assessed carotid characteristics, including intima-media thickness (IMT), distensibility and lumen diameter with B-mode ultrasound, and calculated Young's elastic modulus, cross-sectional wall area and beta-stiffness index. We measured the carotid dorsalis pedis pulse-wave velocity, brachial and central systolic blood pressure (cSBP) and determined metabolic, inflammatory and endothelial activation markers from blood samples. Health behaviours were reported in questionnaires. Results: The hypertensive group presented with higher brachial and central blood pressure, thicker IMT and stiffer carotid arteries (all p < 0.001). However, after adjustment for cSBP but not mean arterial pressure (MAP), all significant differences in carotid characteristics were lost. The carotid thickness measurements did not differ after adjustment for MAP. After adjustment, metabolic, inflammatory and endothelial activation markers did not differ between the two groups. Conclusion: Our results suggest that besides structural changes, functional adaptations are also involved in deterioration of the carotid wall characteristics of hypertensive black South Africans. These results highlight the importance of proper hypertension control in Africa.

Diabetes Research and Clinical Practice

Black populations from sub-Saharan Africa have a high prevalence of cardiovascular disease, which... more Black populations from sub-Saharan Africa have a high prevalence of cardiovascular disease, which places significant strain on public health systems. Aortic stiffness is a prominent risk factor for cardiovascular disease development. We reported earlier that excessive alcohol use predicts aortic stiffness. However, we require a better understanding of other biomarkers involved in stiffness development, beyond alcohol use. Therefore, we determined which biomarkers (metabolic, inflammatory, endothelial activation and oxidative stress) relate to aortic stiffness in young and older black South Africans, self-reporting no alcohol-use. Methods: We included cross-sectional data from young (aged 24.7 ± 3.24 years) black adults participating in the African Prospective study on the Early Detection and Identification of Cardiovascular Disease and Hypertension (African-PREDICT) study (N=216), and fiveyear follow-up data from older (aged 61.6 ± 9.77 years) black adults (N=322) participating in the South African leg of the Prospective Urban and Rural Epidemiology study, conducted in the North West Province (PURE-SA-NWP). We excluded all participants self-reporting alcohol use. We determined biomarkers from blood samples, and measured carotid-femoral pulse wave velocity (PWV). Results: Of all biomarkers investigated in multivariable-adjusted regression analyses, only plasma glucose (R 2 =0.24, β=0.21, p<0.001) and glycated haemoglobin (R 2 =0.22, β=0.17, p=0.002) independently predicted PWV five years later in older adults. We found no other associations in young or older black adults. Conclusion: Dysglycaemia independently predicted aortic stiffness after five years in older black adults. Life-course management of body weight and sugar intake are important in preventing early vascular ageing and subsequent cardiovascular disease development in Africa.

Parents, Gerrit and Angelique, thank you for your love, support, understanding and helpfulness th... more Parents, Gerrit and Angelique, thank you for your love, support, understanding and helpfulness throughout this year. Thank you to Maretha Botes for the language editing of this dissertation.

Increased arterial stiffness is linked to cardiovascular disease development, particularly in bla... more Increased arterial stiffness is linked to cardiovascular disease development, particularly in black populations. Since detrimental health behaviors in young adults may affect arterial stiffness, we determined whether arterial stiffness associates with specific health behaviors, and whether it is more pronounced in young healthy black compared to white adults. We included 373 participants (49% black, 42% men) aged 20–30 years. Mean arterial pressure was higher for blacks than whites (P < .001), but carotid-femoral pulse wave velocity was similar (6.37 vs. 6.36 m/s; P 1⁄4 .89) after adjustment for mean arterial pressure. The black group had higher gamma-glutamyltransferase (GGT) (P < .001), cotinine, reactive oxygen species, interleukin-6, and monocyte-chemoattractant protein-1 (all P .017). Pulse wave velocity related positively and independently to GGT in both groups before and after multiple adjustments (both b 1⁄4 0.15; P .049). Blacks had an unfavorable vascular profile and...

Journal of the American Society of Hypertension : JASH, Jan 4, 2016

Increased arterial stiffness is linked to cardiovascular disease development, particularly in bla... more Increased arterial stiffness is linked to cardiovascular disease development, particularly in black populations. Since detrimental health behaviors in young adults may affect arterial stiffness, we determined whether arterial stiffness associates with specific health behaviors, and whether it is more pronounced in young healthy black compared to white adults. We included 373 participants (49% black, 42% men) aged 20-30 years. Mean arterial pressure was higher for blacks than whites (P < .001), but carotid-femoral pulse wave velocity was similar (6.37 vs. 6.36 m/s; P = .89) after adjustment for mean arterial pressure. The black group had higher gamma-glutamyltransferase (GGT) (P < .001), cotinine, reactive oxygen species, interleukin-6, and monocyte-chemoattractant protein-1 (all P ≤ .017). Pulse wave velocity related positively and independently to GGT in both groups before and after multiple adjustments (both β = 0.15; P ≤ .049). Blacks had an unfavorable vascular profile and...

Journal of Hypertension, 2017

Objective: Black populations exhibit higher arterial stiffness than whites and suffer a dispropor... more Objective: Black populations exhibit higher arterial stiffness than whites and suffer a disproportionate burden of cardiovascular disease. It is therefore important to identify modifiable health behaviours predicting large artery stiffness in blacks. We examined whether traditional cardiovascular risk factors and health behaviours of black South Africans predict large artery stiffness 10 years later. Methods: We included 650 HIV-free participants (32.8% men) and collected data in rural and urban areas of the North West Province in 2005 and 2015. We collected questionnaire data, anthropometry, blood pressure and determined cardiometabolic and inflammatory markers from blood samples. We measured carotid-femoral pulse wave velocity (PWV) at follow-up. Results: A total of 25.3% of our population, aged 65 AE 9.57 years, had a PWV exceeding 10 m/s. In multivariable-adjusted regression analyses, the strongest predictors of PWV were mean arterial pressure, age and heart rate (all P < 0.024). Urban locality (R 2 ¼ 0.31, b ¼ 0.12, P ¼ 0.001), self-reported alcohol use (b ¼ 0.11, P ¼ 0.018) and plasma glucose (b ¼ 0.08 P ¼ 0.023) associated positively with PWV at follow-up. We found a negative association between PWV and BMI (b ¼ À0.15, P ¼ 0.001), and no associations with sex, smoking, inflammatory markers, lipids, liver enzymes or antihypertensive medication. When replacing self-reported alcohol with gamma-glutamyltransferase, the latter associated positively with PWV (b ¼ 0.09, P ¼ 0.023). Conclusion: A health profile associated with excessive alcohol use, including an urban setting, elevated plasma glucose and lower BMI predicts large artery stiffness independently of age and blood pressure in black South Africans over 10 years. This observation prompts urgent public health strategies to target alcohol overuse.

Cardiovascular Journal of Africa

Introduction: An important feature of hypertension is a reduction in large artery distensibility,... more Introduction: An important feature of hypertension is a reduction in large artery distensibility, which may be due to structural and functional adaptations. Black populations are particularly prone to the development of hypertension. We therefore compared the carotid characteristics between fiveyear sustained hypertensive and normotensive black South Africans, and investigated how carotid characteristics relate to cardiometabolic risk factors, inflammation, endothelial activation and health behaviours. Methods: We included HIV-free black South Africans who were either consistently hypertensive (n = 351) or normotensive (n = 241) from 2005 to 2010. We assessed carotid characteristics, including intima-media thickness (IMT), distensibility and lumen diameter with B-mode ultrasound, and calculated Young's elastic modulus, cross-sectional wall area and beta-stiffness index. We measured the carotid dorsalis pedis pulse-wave velocity, brachial and central systolic blood pressure (cSBP) and determined metabolic, inflammatory and endothelial activation markers from blood samples. Health behaviours were reported in questionnaires. Results: The hypertensive group presented with higher brachial and central blood pressure, thicker IMT and stiffer carotid arteries (all p < 0.001). However, after adjustment for cSBP but not mean arterial pressure (MAP), all significant differences in carotid characteristics were lost. The carotid thickness measurements did not differ after adjustment for MAP. After adjustment, metabolic, inflammatory and endothelial activation markers did not differ between the two groups. Conclusion: Our results suggest that besides structural changes, functional adaptations are also involved in deterioration of the carotid wall characteristics of hypertensive black South Africans. These results highlight the importance of proper hypertension control in Africa.