High blood pressure and elevated serum cholesterol are both contributors to morbidity and mortality of cardiovascular disease.1 Epidemiological studies have demonstrated patients with high blood pressure often also have high levels of cholesterol.2–4 However, it is not yet clear if the presence of high cholesterol causes high blood pressure. Several studies have attempted to determine the relationship between these distinct cardiovascular risk factors to better guide treatment and prevention efforts.
To understand the nature of this relationship, Ferrara et al. investigated if serum cholesterol levels might affect blood pressure readings at rest, during ambulatory monitoring, and during sympathetic stimulation known to raise blood pressure [squeezing a handgrip dynamometer for three minutes].5 They measured serum cholesterol levels in 73 newly diagnosed untreated hypertensives, divided the subjects into three groups based on the level of their total cholesterol and compared these blood pressure indicators among the three groups. The three groups were similar with respect to possible confounding variables such as age, sex, body mass index, and smoking history. Blood pressure at rest and during ambulatory monitoring was similar in the three groups. During sympathetic stimulation however, systolic and diastolic blood pressures differed significantly in the three groups, increasing by 16/12, 28/19, and 30/23 mm Hg (p<0.01) in the low, medium, and high cholesterol groups, respectively. In addition, carotid artery intima-media thickness was measured by ultrasound in the three groups. The authors found that there was a significant difference in the intima media thickness between the lowest cholesterol group and the two higher cholesterol groups (p<0.05). The authors suggest that cholesterol levels may affect the development of atherosclerotic vessels and that the stiffer arteries which result might be less able to counteract the effect of isometric exercise on blood pressure.
Sesso et al. conducted a prospective of 16 130 women in the Women’s Health Study who had neither high cholesterol (based on current treatment or physician diagnosis) nor high blood pressure (based on current treatment, physician diagnosis, or ≥140/90 mm Hg) at baseline.6 Patient history was also obtained on entry in the study to ascertain other cardiovascular risks including age, BMI, smoking, alcohol use, exercise, and family history. Over the 10.8 years of follow-up, 4593 women developed hypertension.
The authors divided the study participants into quintiles based on baseline levels of total cholesterol. The relative risk (RR) of developing hypertension tended to increase as the level of cholesterol increased among previously healthy women (p = 0.002 for trend).
They hypothesize that one or more possible mechanisms may be in play. Dyslipidemic atherosclerosis may cause structural damage to the lining of the arteries that results in reduced elasticity. Alternatively, or in addition, increases in total cholesterol may impair vasodilation. It is also possible that the associated hypertension may reflect damage to renal vasculature caused by dyslipidemia. Another consideration is that both hyperlipidemia and hypertension are components of the metabolic syndrome and might share a common pathway that explains their coincidence.
Borghi et al. studied 70 men under the age of 45 who at study onset had high normal blood pressure (systolic range between 130 and 139 mm Hg and diastolic range between 85 and 89 mm Hg) in a 15 year prospective study.7 The main outcome measure was the development of stable hypertension (diastolic blood pressure >95 mm Hg). After adjusting for age, resting blood pressure, family history of hypertension, and BMI, the authors found that men who had high cholesterol at entry (>200 mg/dL) had a higher incidence of stable hypertension compared to participants with normal cholesterol (≤199) (relative risk 2.1; 95% confidence interval [1.7 – 5.5], p<0.0001). By the end of the study, stable hypertension had developed in 48.9% of patients with high cholesterol, compared to 23.7% in subjects with normal cholesterol (p<0.01). In addition, the authors found that study participants with high cholesterol had a statistically significantly enhanced response to stress as measured by blood pressure readings during a mental arithmetic challenge. The authors speculate this may reflect a negative effect of lipid abnormalities on peripheral vascular tone that might affect blood pressure regulation.
Several large studies have demonstrated a relationship between dietary cholesterol and blood pressure.8–10 The INTERMAP study was a study of micro and macro nutrients and blood pressure. Sakurai et al. used cross-sectional data from the INTERMAP study to examine the relationship between dietary cholesterol and blood pressure in 4680 people from around the world.10 Linear regression analysis showed that intake of dietary cholesterol was directly related to systolic blood pressure for all participants. The authors propose that in the same way that elevated serum cholesterol levels have been shown to correlate with endothelial dysfunction and arterial stiffness, dietary cholesterol may have a similar influence.
References
- Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension 2017; 71 (19): e127-e248.
- Laurenzi M, Mancini M, Menotti A, et al. Multiple risk factors in hypertension: results from the Gubbio study. J Hypertens Suppl 1990; 8 (1): S7-12.
- MacMahon SW, Macdonald GJ, Blacket RB. Plasma lipoprotein levels in treated and untreated hypertensive men and women. The National Heart Foundation of Australia Risk Factor Prevalence Study. Arteriosclerosis 1985; 5 (4): 391-396.
- Castelli WP, Anderson K. A population at risk: prevalence of high cholesterol levels in hypertensive patients in the Framingham study. Am J Med 1986; 80 (2 SUPPL. 1): 23-32.
- Ferrara LA, Guida L, Iannuzzi R, Celentano A, Lionello F. Serum cholesterol affects blood pressure regulation. J Hum Hypertens 2002; 16 (5): 337-343.
- Sesso HD, Buring JE, Chown MJ, Ridker PM, Gaziano JM. A prospective study of plasma lipid levels and hypertension in women. Arch Intern Med 2005; 165 (20): 2420-2427.
- Borghi C, Veronesi M, Bacchelli S, Esposti DD, Cosentino E, Ambrosioni E. Serum cholesterol levels, blood pressure response to stress and incidence of stable hypertension in young subjects with high normal blood pressure. J Hypertens 2004; 22 (2): 265-272.
- Stamler J, Liu K, Ruth KJ, Pryer J, Greenland P. Eight-year blood pressure change in middle-aged men: relationship to multiple nutrients. Hypertension 2002; 39 (5): 1000-1006.
- Stamler J, Caggiula A, Grandits GA, Kjelsberg M, Cutler JA. Relationship to blood pressure of combinations of dietary macronutrients. Findings of the Multiple Risk Factor Intervention Trial (MRFIT). Circulation 1996; 94 (10): 2417-2423.
- Sakurai M, Stamler J, Miura K, et al. Relationship of dietary cholesterol to blood pressure : the INTERMAP study. J Hypertens 2011; 29 (2): 222-228.
