Blood Pressure and Arterial Stiffness in Kenyan Adolescents With alpha(+)Thalassemia

Etyang AO, Khayeka-Wandabwa C, Kapesa S, Muthumbi E, Odipo E, Wamukoya M, Ngomi N, Haregu T, Kyobutungi C, Tendwa M, Makale J, Macharia A, Cruickshank JK, Smeeth L, Scott JA, Williams TN
J Am Heart Assoc. 2017;6

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BACKGROUND: Recent studies have discovered that alpha-globin is expressed in blood vessel walls where it plays a role in regulating vascular tone. We tested the hypothesis that blood pressure (BP) might differ between normal individuals and those with alpha(+)thalassemia, in whom the production of alpha-globin is reduced. METHODS AND RESULTS: The study was conducted in Nairobi, Kenya, among 938 adolescents aged 11 to 17 years. Twenty-four-hour ambulatory BP monitoring and arterial stiffness measurements were performed using an arteriograph device. We genotyped for alpha(+)thalassemia by polymerase chain reaction. Complete data for analysis were available for 623 subjects; 223 (36%) were heterozygous (-alpha/alphaalpha) and 47 (8%) were homozygous (-alpha/-alpha) for alpha(+)thalassemia whereas the remaining 353 (55%) were normal (alphaalpha/alphaalpha). Mean 24-hour systolic BP +/-SD was 118+/-12 mm Hg in alphaalpha/alphaalpha, 117+/-11 mm Hg in -alpha/alphaalpha, and 118+/-11 mm Hg in -alpha/-alpha subjects, respectively. Mean 24-hour diastolic BP +/-SD in these groups was 64+/-8, 63+/-7, and 65+/-8 mm Hg, respectively. Mean pulse wave velocity (PWV)+/-SD was 7+/-0.8, 7+/-0.8, and 7+/-0.7 ms(-1), respectively. No differences were observed in PWV and any of the 24-hour ambulatory BP monitoring-derived measures between those with and without alpha(+)thalassemia. CONCLUSIONS: These data suggest that the presence of alpha(+)thalassemia does not affect BP and/or arterial stiffness in Kenyan adolescents.