Risks factors

This chapter outlines the major known risk factors for TIA and stroke. Knowledge of these risk factors is necessary in order to understand the aetiology of TIA and stroke, to predict risk and to develop effective preventive strategies. 

There are many more data on risk factors for acute coronary events than for ischemic stroke (Bhatia and Rothwell 2005) because of more intensive investigation in routine clinical practice and because heart disease receives much higher levels of research funding than stroke (Rothwell 2001 Pendlebury 2007). 

Age is the strongest risk factor for ischemic stroke of all subtypes and for primary intracerebral hemorrhage, but it is less important for subarachnoid hemorrhage (Bamford et al. 1990 Rothwell et al. 2005). Overall stroke incidence at age 75-84 is approximately 25 times higher than at age 45-54 (see Fig. 1.2). 

Factors associated with an increased risk ofvascuiar disease 

Evidence of pre-existing vascuiar disease Transient ischemic attacks Cervical arterial bruit and stenosis Myocardial infarction/angina 

There is a great deal of data concerning risk factors for VAP. These factors are important since they may contribute to the development of effective prevention programs by indicating which patients may be most likely to benefit from prophylaxis against pneumonia. We herewith discuss the most relevant risk factors for endogenous infection in VAP, although data on many of these factors continue to be controversial. These risk factors are listed in Table 1. 

The distribution of microorganisms, especially potentially resistant bacteria, differs with prior antibiotic therapy. Likewise, previous antibiotic administration may influence the development of VAP in two different ways its use may be associated with a protective effect against early-onset pneumonia, or it may be associated with an increased risk of late-onset 

Decrease in pressure of the tracheal tube cuff Stress-ulcers prophylaxys (anti-H2) Tracheostomy Coma and head trauma Nasogastric tube and gastric distension Patient transport 

The diagnostic tests performed on suspicion of VAP have two objectives. The first is to determine whether the patient really has an infectious pulmonary process as indicated by the signs and symptoms leading to the use of these tests. The second is the isolation of the causative microorganisms of the disease. 

Abbreviations. Pa02, oxygen arterial pressure FiOj, inspired fraction of oxygen ARDS, acute respiratory distress syndrome. 

Some patients first sign of morbidity from elevated lOP can be presentation with sudden loss of vision due to a central retinal vein occlusion (CRVO). Elevated lOP is the second most common risk factor for CRVO behind systemic hypertension. 

Cognitions are beliefs that contribute to drug use behavior. The following are important beliefs that have been associated with drug use  

Common emotions associated with addictive processes include the following  

Many chemically dependent clients have difficulties identifying and regulating their emotions, much to their detriment. 

Stability testing is a technical experiment conducted at well-defined conditions, for example at fixed temperatures and humidities. These testing conditions provide a model for the climatic conditions in the environment in which the drug substance or medicinal product is stored and shipped during shelf-life. This environment can be sufficiently described by parameters influencing the stability, mainly heat and 

There are, however, several other risk factors, which could have an impact on the stability of a drug substance or a drug product  

In the following, only the external risk factors heat and moisture are evaluated. 

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Type of pollutant Weight % of volatile organic compounds contained In exhaust gas Relative risk factor... 

Cholesterol is biosynthesized in the liver trans ported throughout the body to be used in a va riety of ways and returned to the liver where it serves as the biosynthetic precursor to other steroids But cholesterol is a lipid and isn t soluble in water How can it move through the blood if it doesn t dis solve in if The answer is that it doesn t dissolve but IS instead carried through the blood and tissues as part of a lipoprotein (lipid + protein = lipoprotein) The proteins that carry cholesterol from the liver are called low density lipoproteins or LDLs those that return it to the liver are the high-density lipoproteins or HDLs If too much cholesterol is being transported by LDL or too little by HDL the extra cholesterol builds up on the walls of the arteries caus mg atherosclerosis A thorough physical examination nowadays measures not only total cholesterol con centration but also the distribution between LDL and HDL cholesterol An elevated level of LDL cholesterol IS a risk factor for heart disease LDL cholesterol is bad cholesterol HDLs on the other hand remove excess cholesterol and are protective HDL cholesterol IS good cholesterol... 

In 1986, the FDA s Sugars Task Force assessed the impact of sugar consumption on human health and nutrition and concluded that sucrose is not an independent risk factor for heart disease, nor does it cause or contribute to the development of diabetes (62). Although diet is important after the onset of diabetes, sucrose can be well tolerated by insulin-dependent diabetics (63—65). 

Homocysteine arises from dietary methionine. High levels of homocysteiae (hyperhomocysteinemia) are a risk factor for occlusive vascular diseases including atherosclerosis and thrombosis (81—84). In a controlled study, semm folate concentrations of <9.2 nmol/L were linked with elevated levels of plasma homocysteiae. Elevated homocysteine levels have beea associated also with ischemic stroke (9). The mechanism by which high levels of homocysteine produce vascular damage are, as of yet, aot completely uaderstood. lateractioa of homocysteiae with platelets or eadothehal cells has beea proposed as a possible mechanism. Clinically, homocysteine levels can be lowered by administration of vitamin B, vitamin B 2> foHc acid. 

Homocysteine has been identified as an independent risk factor for atherosclerosis (32) and thus metaboHc control over homocysteine levels has major health implications. 

Hypertension is one of the two principal risk factors of many cardiovascular diseases, such as coronary heart disease (CHD), stroke, and CHF. Individuals are considered hypertensive if their systoHc arterial blood pressure is over 140 mm Hg (18.7 Pa) or their diastoHc arterial blood pressure is over 90 mm Hg (12 Pa). Over 60 million people, or one-third of the adult population in the United States are estimated to be hypertensive (163). About 90% of these patients are classified as primary or essential hypertensive because the etiology of their hypertension is unknown. It is generally agreed that there is a very strong genetic or hereditary component to this disease. 

The fact that ceU culture-derived products are often injected into humans as therapeutic agents makes it imperative that there be no component in the final product that can pose a potential health risk to the patient. Health risks can be introduced into a product from many sources including the ceUs themselves raw materials, such as semm, media components, etc materials used in purification, eg, antibodies and external contamination. Eor a therapeutic product such risk factors are identified at the outset and ways of reducing them to acceptable levels are designed into the process. Before a product is released by the EDA the manufacturer has to demonstrate this risk reduction by rigorous validation of the process. 

Most of these methods are commonly employed in the downstream processing of the desired ceU culture technology product. Hence, most of the time it is only necessary to demonstrate that the designed process is reducing the putative risk factors to acceptable levels. Validation methods employed for risk reduction are discussed in the Hterature (25). 

The beneficial effects of dietary fiber, including both soluble and iasoluble fiber, are generally recognized. Current recommendations are for daily iatakes of 20—35 g ia a balanced diet of cereal products, fmits, vegetables, and legumes. However, the specific preventive role of dietary fiber ia certaia diseases has beea difficult to estabUsh, ia part because dietary risk factors such as high saturated fat and high proteia levels are reduced as fiber levels iacrease. 

Another study (84), which enrolled men and women between the ages of 21—55 who had mild hypertension and no recognizable cardiovascular risk factors, showed no significant differences in mortaUty between dmg- and placebo-treated patients. Significant reductions in hypertensive complications were noted, but atherosclerotic complications were not reduced. 

Breast Cancer. Many studies have observed low incidences of hormone-dependent cancers, particularly breast cancer, in Asian countries compared with Western countries and it is becoming increasingly accepted that dietary factors play an important role. Although breast cancer can occur in either males or females, only about 1 % of all cases occur in men, and male breast cancer is a rare disease in all parts of the world." Although there appear to be some similar risk factors for breast cancer in males and females, there is no indication in the literature that diet is either a risk or a protective factor for male breast cancer. The development of breast cancer is known to be highly dependent on the hormones associated with female reproductive functions, while established genetic factors have been... 

Several studies have investigated the role of dietary factors in prostate cancer risk, but results appear inconsistent. Significant effects have not been detected for dietary soya products certain vegetables, beans, fruit, rice and seaweed appear to be protective in some studies, while another has shown no protective effect from seaweed or vegetable consumption. In addition, a number of other risk factors have been shown to be associated with an increased risk of this cancer, including meat and dairy products and carotenoids. 

In adults, a few areas may require further study. For example, there is a report of soya consumption causing an increased incidence of hyperplastic epithelial cells in the nipple aspirate fluid of pre- and postmenopausal women.This could constitute a risk factor for breast cancer. Also, the use in herbal medicine of particular plants emphasises that these species have the potential to cause physiological changes. Consequently, the increasing public interest in the use of herbal medicines could lead to unintended (adverse) effects, particularly as most... 

Silverman, D. T., Levin, L. 1., Hoover, R. N., and Hartge, P. (1989). Occupational risk factors of bladder cancer in the United States I. White men. /. Natl. Cancer Inst. 81, 1472 -14SI, . Silverman, D. T, Levin, L. L, and Eloovet, R. N. (1990). Occupational risk factors of hladLler cancer among white women in the United States. Am. j. Epidemiol. 1.32, 453-461. 

Sicmiarycki, )., Dewar, R., Nadon, L.., and Gerin, M. (1994). Occupational risk factors for bladder cancer Results from a case-control study in Montreal, Quebec, Canada. Am. J. Epide-miol. 140, 1061-1080. 

Sieiniatycki, j. (Fcl.) (1991). Risk Factors for Cancer in the Workplace, CRC Press, Boca Raroii, FI,. 

Low-density lipoprotein (LDL) (Section 26.11) A protein which carries cholesterol from the liver through the blood to the tissues. Elevated LDL levels are a risk factor for heart disease LDL is often called bad cholesterol. ... 

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