Dietary information has been collected repeatedly from a 10% sub-sample of the ALSPAC cohort (around 1000 children) at the following ages: 4 months, 8 months, 1 1/2 years, 3 1/2 years, 5 years and 7 years. Information was collected by a one-day unweighed food record at 4 months, and by a three-day unweighed food record at all other ages. All the dietary data have been coded and prepared and are ready for use. Information on the use of salt at the table and in cooking is available at the following ages: 3 1/2 years, 5 years, and 7 years.

Information is available on a range of socio-demographic and lifestyle factors, including the following: parental education, social class and age, housing tenure, financial difficulties and some questionnaire information about physical activities (e.g. time spent watching TV, walking, cycling etc.).

Table 1 shows mean non-discretionary sodium intakes in ALSPAC from 4 months to 3 1/2 years, in comparison with target average sodium intakes suggested by the Scientific Advisory Committee on Nutrition to the Food Standards Agency.

Table 1. Non-discretionary intakes of sodium (mg) from 4 months to 3 1/2 years and the proportion of children consuming at or below target intakes

____________Percentiles____________ % below

Age Mean (sd) 2.5 25 50 75 97.5 Target target

4 months 180 (59) 92 140 171 210 324 less than 400 99.4

8 months 612 (324) 216 374 546 772 1402 400 28.4

18 months 1432 (439) 706 1140 1384 1668 2472 800 4.9

43 months 1823 (470) 1006 1516 1789 2091 2883 800 0.6

It can be seen that from the age of 8 months the great majority of children are consuming in excess of SACN target intakes for sodium from non-discretionary sodium intake. These figures do not include an estimation of salt added at the table or added to vegetables during cooking. However, the proportion of sodium derived from non-discretionary sources is likely to be lower than it is in adults (15-20%), as most parents do not usually allow their children to add salt at the table, and many report avoiding adding salt when cooking for children. (At age 5 only 15.6% regularly added salt to their children's food in cooking, 47.9% reported never adding it, while only 1.4% allowed their child to add salt at table regularly and 66.1% never did this).

Data from the diaries collected at 4 months suggests that breastfed infants had a lower sodium intake than formula fed infants at this age. Other work has shown a difference in blood pressure at age 7 years between breastfed and formula fed infants.

We will use the data collected in ALSPAC to answer the following research questions:

1. What are the main dietary sources of salt at each age (4m, 8m, 1 1/2y, 2y, 3 1/2y, 5y, 7y)?

2. What food groups distinguish most between children with high and low sodium intakes at each age?

3. How does salt intake relate to intakes of other foods and nutrients relevant to cardiovascular health, and to sociodemographic and lifestyle factors?

4. How well does salt intake "track" throughout early childhood?

5. Do breastfed infants subsequently go on to have lower salt intakes than formula-fed infants.