Nutrition can influence the risk for a wide variety of diseases, and, conversely, malnutrition can result from illness. Nutrition affects various factors that predispose to medical illness, including immune function, body composition, and micronutrient status. The three leading causes of death are related to nutrition: heart disease, cancer, and cerebrovascular disease.<sup>62Peters K.D., Kochanek K.D., Murphy S.L. Deaths: Final Data for 1996. National Vital Statistics Reports Hyattsville, MD: National Center for Health Statistics (1998).  vol 47, no. 9.

Cliquez ici pour aller à la section Références</sup> Nutrition can affect functional status and the ability to carry out activities of daily living as well as the quality and enjoyment of life. Identifying abnormalities in nutritional status, mainly deficiencies or in some cases excesses, through screening is important to decrease morbidity and mortality in the screened population. This article first describes the types and prevalence estimates of malnutrition. Following this, the goals of nutrition screening are outlined. Screening and nutrition assessment tools and methods are then covered for ambulatory and hospital populations. Finally, detailed nutrition assessment is discussed.

Health status can be thought of on a continuous scale ranging from optimal health on one end to clinical disease on the other, and nutritional factors can move people either way along this continuum. Nutritional health promotion activities usually operate on one end of this scale in such a way so as to move people farther toward optimal health. Nutrition screening has historically been concerned with the other end of the scale, identifying patients at high risk so that they can then undergo further nutrition assessment in hopes of preventing or treating clinical disease. Nutrition screening could also be applied in the context of health promotion, however. In primary care, for example, it can and should be part of other health promotion activities.

Nutrition screening is the process of identifying patients at high nutritional risk so that more extensive nutrition assessment can be performed. Nutrition assessment is a more detailed evaluation and interpretation of multiple parameters and seeks to define the risk of developing nutrition-related medical complications. It can also be used to monitor the course of nutritional therapy. Thus, nutrition screening is a brief evaluation to identify a subset of people at high risk, whereas nutrition assessment is a more complex process applied to this subset to delineate further their nutrition status. The distinction between screening and assessment can be blurred, however. The ultimate goal of both of these activities is to identify factors in individuals that can be altered through nutritional support to improve outcome in the screened population. Because nutrition screening and assessment are inextricably linked, this overview addresses both of these processes. Nutrition screening may also influence case finding in clinical practice. For example, a history of recent weight loss and evidence of malnutrition along with other signs and symptoms may prompt medical evaluation to search for possible causes, such as cancer or other conditions.

Another way of influencing nutritional status in a positive manner is the public health approach, in which education and other efforts are targeted at all members of the population rather than screening for high-risk individuals. An example is the National Cancer Institute's Five-A-Day program, which encourages people to consume at least five servings of fruits and vegetables per day to decrease the risk of cancer.<sup>31Havas S., Heimendinger J., Reynolds K., et al. 5 a day for better health: A new research initiative J Am Diet Assoc 1994 ;  94 : 32 [cross-ref]

Cliquez ici pour aller à la section Références</sup> The advantage of the public health approach is targeting and, it is hoped, influencing most of the population, and therefore it is best used in situations in which the entire population can potentially benefit, such as in increasing fruit and vegetable consumption. This approach, however, would not identify or help high-risk individuals with specific nutritional problems. For this reason, the public health approach and the screening approach should be viewed as complementary.

Nutrition screening can be applied to different populations. The very old are at high risk of nutritional problems. The number of elderly people in the United States has been increasing and will continue to increase in the coming years, which will, in turn, increase the number of people at risk for nutritional problems. Nutrition screening can be used in the home, ambulatory, institutional, or hospital settings. Nutrition risk and the effectiveness of nutrition screening vary by setting. Hospitalized patients are at highest risk, and the Joint Commission on Accreditation of Healthcare Organizations requires nutrition screening for all patients admitted to the hospital.<sup>41Joint Commission on Accreditation of Healthcare Organizations Comprehensive Accreditation Manual for Hospitals: The Official Handbook Oakbrook Terrace, IL: Joint Commission on Accreditation of Healthcare Organizations (1998). 

Cliquez ici pour aller à la section Références</sup> The tool and questions used for screening depend on the characteristics of the population screened and the goals of the screening program.