View source for 4. Epidemiology of malnutrition and nutritional deficiencies

* Micronutrient deficiency is widespread in developing countries, affecting 2 billion people worldwide
* Deficiency affects the most vulnerable groups most commonly
* Most common deficiencies
** Iron
** Vitamin A
** Iodine
* Malnutrition = inadequate or excess intake of a nutrient, leading to infections and disorders
* Underweight malnutrition – large problem in the developing world
** Affects mainly children and women
** Malnutrition increases risk for children to die from malaria, meningitis, pneumonia, gastroenteritis

Epidemiology of malnutrition

* Epidemiology is the study of the distribution and determinants of diseases and other health outcomes in human populations
* Types of studies in nutritional epidemiology
** Descriptive studies – an observational study that describes the characteristics of a population
*** Describes the nutritional state of a population
*** National surveys are often used
** Ecological studies – an observational study that measures the incidence of a disease in a population
*** Can compare how the incidence of a disease in a population changes over time
*** Can study whether certain populations have higher incidence of disease (like certain ethnicities, religions)
*** Can study immigrants to assess the contributions of genetic and environmental factors
** Case-control studies – a retrospective observational study that compares people with a disease and without a disease and looks for possible risk factors
** Cohort studies – a prospective study that compares two groups, one group with a risk factor and another group without and compares their incidence of disease
** Intervention trials – a double blind experimental study where random subjects are assigned into two groups. One group receives a treatment, the other not. Health outcomes are compared.

Types of malnutrition

* Growth failure
** Acute malnutrition
*** Kwashiorkor
**** Severe protein malnutrition but without total calorie deficiency
**** Symptoms
***** Oedema
***** Pigmentation changes of skin and hair
***** Impaired growth and development
***** Ascites
***** Liver disease
*** Marasmus
**** Severe protein and calorie malnutrition
**** Symptoms
***** Growth retardation
***** Wasting of subcutaneous fat, muscle
** Chronic malnutrition
*** Shortness
*** Cognitive dysfunction
* Micronutrient malnutrition
** Iron deficiency
*** Most common nutritional disorder – 2 billion people worldwide
*** Causes anaemia
*** Very prevalent in pregnant women and preschool children in developing countries
*** Aggravated by parasite infection, malaria, HIV, TB
*** Health effects
**** Fatigue
**** Poor pregnancy outcome
**** Impaired physical and cognitive development
**** Increased morbidity in children
*** Prevention
**** Increase iron intake
**** Control infection
**** Improve nutritional status
** Vitamin A deficiency
*** Major cause of blindness in Africa, south-east Asia
*** Affects mostly children and pregnant women
*** Prevention
**** Supplementation
**** Increased breastfeeding
**** Promotion of vitamin A-rich diet
**** Fortification of food
***** Golden rice – a type of rice fortified with vitamin A
** Iodine deficiency

Cachexia

* = a complex metabolic syndrome characterised by loss of muscle with or without loss of fat, due to an underlying illness
* Frequently seen in COPD, chronic kidney disease, cancer
* Causes weight loss
* Anorexia, inflammation, insulin resistance and protein catabolism as associated with cachexia
* Not the same as starvation!
* Increases morbidity

Intervention of malnutrition and nutritional deficiencies

* Determine etiology of malnutrition
** Parasite
** Infection
** Increased demand
** Poor diet
* Effective measures
** Improve water supply, sanitation, hygiene
** Improve access to adequate amounts of healthy food
** Supplementation
*** When deficiency is severe
*** Can be used as preventative measure in high-risk populations
*** Cost-effective
** Fortification of foods (adding nutrients to foods)
*** Not appropriate in severe deficiency
*** Requires participation of the food industry
** Diversify the diet
*** Introduce nutrient-rich foods in the diet
*** Change dietary habits
** Change agricultural habits

[[Category:Public health 4 - Preventive medicine]]