The purpose of this study is to determine whether a weekly supplement of vitamin D to low birth weight term infants will reduce their mortality and hospital admissions and improve their immunity.

We are conducting a randomised controlled trial of weekly oral vitamin D supplements to low birth weight (< 2.5 kg) term infants born in a large government hospital catering to a low-middle income population in Delhi. Mothers and infants are recruited at delivery and given weekly vitamin D supplements or placebo until 6 months of age. Data on infant morbidity, sun exposure and diet, with particular emphasis on breast milk and other milk intake, is collected by fieldworkers visiting the homes each fortnight. Mothers are encouraged to bring their infants to the hospital in case of any illness and at these visits the infant is seen by the project doctor who treats the infant and records additional morbidity data. At 6 months blood samples are being collected from a 20% random subsample of infants for measurement of 25OHD and indicators of immune activation. The primary outcome is mortality or incidence of any illness requiring admission to hospital.

Inclusion Criteria:

• Born at term, as determined from last menstrual period
• Weighing < 2.5 kg
• Resident within 12 km of the hospital and expected to continue living in the area for the following 6 months
• With no severe congenital abnormalities
• No morbidity severe enough to be expected to result in death before 7 days due to severe respiratory distress, shock, pulmonary sepsis, etc.
• Parental informed consent