Diet, infection and wheezy illness: lessons from adults

Area of Science:

• Epidemiology
• Allergy and Immunology
• Nutritional Science

Background:

• Rising incidence of asthma and atopic diseases observed in prosperous nations.
• Investigated potential links between reduced childhood infections and dietary changes.
• Examined the impact of family size and infections on eczema, hay fever, and asthma development.

Purpose of the Study:

• To investigate the relationship between childhood infections, family size, and the development of atopic diseases.
• To explore the role of dietary factors, specifically vitamin C, vitamin E, and saturated fats, in respiratory health.
• To determine if maternal diet during pregnancy influences offspring's predisposition to atopy and asthma.

Main Methods:

• Longitudinal cohort study of individuals since 1964, originally sampled from primary schoolchildren.
• Dietary intake assessment through two separate studies focusing on vitamin C, vitamin E, and saturated fats.
• Biochemical analysis of plasma vitamin and triglyceride levels.

Main Results:

• Larger family size was associated with reduced risk of hay fever and eczema, but not asthma.
• Increased number of childhood infections correlated with a higher likelihood of asthma; measles offered some protection.
• Lowest intake of vitamin C increased bronchial hyper-reactivity risk seven-fold; lowest saturated fat intake provided ten-fold protection.
• Lowest vitamin E intake increased adult-onset wheezy illness risk five-fold; lowest vitamin C intake doubled the risk.

Conclusions:

• Childhood infections, contrary to some hygiene hypotheses, appear to increase asthma risk.
• Dietary factors, including low intake of vitamins C and E and high saturated fat intake, are significantly associated with increased risk of atopic diseases and wheezy illnesses.
• Maternal dietary changes may predispose offspring to atopy and asthma, warranting further investigation in pregnant women and their children.