Continued from last week

Causes Of Primary Hypertension
Hypertension is referred to as  essential (primary) when the doctor is unable to identify a specific cause. It is by far the most common type of high blood pressure.

The causes of this type, while unknown, are likely to be a complex combination of genetic, environmental, and other factors.

Genetic Factors: A number of genetic factors or interactions between certain body compositions of an individual play a major role in causing essential hypertension.

Gene suspects include those that regulate a group of hormones known collectively as the Renin-Angiotensin-Aldosterone System (RAAS). This system influences all aspects of blood pressure control, including blood vessel contraction, sodium and water balance and cell development in the heart. Studies suggest that some people with essential hypertension may also inherit abnormalities of the sympathetic nervous system. This is the part of the nervous system that controls heart rate, blood pressure, and the diameter of the blood vessels.

Causes Of Secondary Hypertension
Secondary hypertension is caused by a defined underlying medical disease or other factor (such as medications) that elevates blood pressure. Many different medical diseases are associated with secondary hypertension. These conditions can also make high blood pressure more difficult to control.

They include:
Diabetes: Hypertension is strongly associated with diabetes; both Type 1 and Type 2. Kidney damage (diabetic kidney disease) is generally the cause of high blood pressure in people with diabetes.

Kidney Disease: Kidney disease is the most common cause of secondary hypertension. In addition to diabetic nephropathy, many other types of kidney diseases can cause hypertension. Renal artery stenosis involves the narrowing of the renal (kidney) artery and is usually caused by atherosclerosis. Other types of kidney diseases associated with hypertension are polycystic kidney disease and renal parenchymal disease.

Endocrine Disorders: Adrenal tumours (pheochromocytoma, aldosteronism), thyroid disorders, and cushion syndrome can all cause secondary hypertension.

Risk Factors For Hypertension
Within the last decade, the number of Nigerians with high blood pressure has increased remarkably. About 20 – 30 per cent of people with high blood pressure are unaware that they have it. People who are diagnosed with pre-hypertension (blood pressure ranges from 120 - 139 / 80 - 89mmHg) are at increased risk of developing high blood pressure.

Age and Gender: Age is the major risk factor of hypertension. Blood pressure increases with age in both men and women, and, in fact, the lifetime risk for developing hypertension is nearly 90 per cent. The risks for high blood pressure increases in men over age 45 and women over age 55. Hypertension is also becoming more common in children and teenagers. Among younger people, boys are at a higher risk for developing high blood pressure than girls.

Race and Ethnicity: Compared to caucasians and other ethnic groups, blacks are much more likely to have high blood pressure. Race and ethnicity induced hypertension account for over 40 per cent of all deaths in this group. High blood pressure tends to start at a younger age among blacks; it is often more severe and causes greater risks for premature death from heart attack, stroke, heart failure, and kidney failure.

Family History: People with parents or other close relatives, who have high blood pressure, have an increased risk of developing it themselves.

Obesity: About a third of patients with high blood pressure are overweight. Even moderately obese adults have double the risk of hypertension than people with normal weights. Children and adolescents who are obese are at a greater risk for developing high blood pressure when they reach adulthood.

Some factors are basically lifestyle-related and these are:

Smoking: Cigarette smoking is a major risk factor for developing high blood pressure.

Excessive Salt consumption: Eating too much salt (sodium) can increase the risk for developing high blood pressure. Similarly, a diet that is too low in potassium can make the body accumulate too much sodium. Sodium and potassium are important regulators of fluid balance in cells.

Alcohol: Chronic heavy alcohol use can increase blood pressure. Women may be more sensitive than men to the blood pressure effects of alcohol.

Physical Inactivity: A sedentary lifestyle and lack of physical activity can increase the risk of becoming overweight.

Stress: Mental and emotional stress can cause a temporary increase in blood pressure. Chronic stress can lead to engaging in unhealthy behaviours (overeating, smoking, alcohol use, lack of exercise) that contribute to high blood pressure.

Complications Of Hypertension
Hypertension places stress on several organs (called target organs), including the kidneys, eyes, brain and the heart, causing them to deteriorate over time. High blood pressure contributes to 75 per cent of all strokes and heart attacks. It is particularly deadly in blacks. Risk of complications or rapid progression of hypertension becomes more likely in the presence of other risk factors, including significant elevation of blood pressure, increasing age, smoking, abnormal cholesterol, family history of premature heart disease, obesity, diabetes, coronary artery disease, and other evidence of vascular disease.

To be continued next week