Doctor: Michèle Cherfane

Title: Non-pharmacological determinants of hypertension at the population level

Supervisor: Jacques Blacher

Doctoral school: ED 146 Doctoral school Galilée, University Sorbonne Paris Nord

Date of thesis defense: 12/2019

Jury: Sébastien Czernichow, Marie Zins, Emmanuelle Kesse-Guyot, Alexandre Vallée, Pascale Salameh

Thesis summary:

Hypertension is the most common chronic disease worldwide and a significant risk factor for cardiovascular diseases. Modifiable risk factors contribute partially to an increasing prevalence and inadequate blood pressure control. On this basis, non-pharmacological recommendations are available in worldwide guidelines for the prevention and management of hypertension. These measures include: maintain a normal body weight, engage in regular physical activity, limit alcohol consumption, reduce dietary salt intake and adhere to a healthy diet. OBJECTIVES: The objective of this thesis is to study the determinants of high blood pressure and to evaluate the relationship between lifestyle behavior and hypertension. In particular, the aim is to investigate the influence of an unhealthy behavior on blood pressure and the magnitude of the individual and combined effect of lifestyle factors on hypertension and blood pressure control. METHODS: Cross-sectional analyses were conducted using data from a representative sample of the adult Lebanese population and the French CONSTANCES cohort study. The Lebanese sample consisted of 2088 adults aged 20 years and above randomly selected following a sampling scheme across Lebanon. While CONSTANCES is an ongoing prospective cohort that included between February 2012 and January 2018 a total of 87,808 volunteer participants aged 18–69 randomly selected from the National Health Insurance Fund. In both studies, blood pressure measurements were done following standard operational procedures and lifestyle behaviors were assessed using self-reported validated questionnaires. Mostly, logistic regression models and general linear models were used to estimate the magnitude of the associations and to study adjusted mean blood pressure parameters, respectively. Adjusted odds ratios were presented along with 95% confidence interval. Statistical analyses were conducted using different statistical analysis software. RESULTS: Results of this thesis describe a high prevalence of hypertension and poor blood pressure control among treated individuals in the Lebanese population. While in France, epidemiologic data are in accordance with results of recent studies. From the conducted 3 analyses, increased body mass index (obesity and overweight), heavy alcohol consumption and non-adherence to dietary recommendations were seen to be independently associated with hypertension and poor blood pressure control, and they influenced systolic blood pressure levels. Controversial results were seen with physical activity in both studies and across different study populations. In terms of the magnitude of the association, body mass index and adherence to dietary approaches to stop hypertension (DASH) diet seem to have the biggest impact on increasing the odds of hypertension and uncontrolled blood pressure. Moreover, a combination of unhealthy behavior increased the odds of hypertension by more than 1.5 times, which highlighted the detrimental effect of an overall poor lifestyle on the risk of hypertension. Furthermore our findings suggest that the extent to which these factors are associated with hypertension is different by gender. CONCLUSION: Findings of this thesis provided needed epidemiologic data on hypertension in Lebanon and France. They emphasize that non-adherence to widely recommended lifestyle modifications has important impact on the risk of hypertension and influences BP control. From a population-based perspective, these findings promote that a global healthy lifestyle through improvement of modifiable behaviors could have major benefits in the prevention of hypertension.

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