For participants and public

Pregnant mothers attending the antenatal clinic at Aberdeen Maternity Hospital were invited to join. There were 2000 mothers recruited at 12 weeks gestation between 1997 and 1999.

When enrolled, mothers filled in a questionnaire letting us know whether they had asthma or other allergies. Mothers then had skin allergy testing to see what they were allergic to. Mother's blood was collected and nutrient levels measured. Finally, mothers completed a food diary 32 weeks into the pregnancy so that we could see what they were eating.

We also obtained ultrasound measurements of the babies in early and mid pregnancy.

Questionnaires were completed by parents to let us know whether their child had asthma or allergy symptoms at 6, 12 and 24 months of age.

When the children reached their 5^th , 10^th and 15^th birthdays they completed questionnaires and had breathing and allergy tests.

We are excited about what we have found so far.

1. We have found that low amounts of vitamin E, D and zinc in the diet during pregnancy were associated with increased wheeze and eczema in children between age 2 and 15 years. These results make sense when we compare them to the General Household and National Diet studies that have also been carried out that show a decline in vitamin E consumption in UK between 1950 and 2000. This suggests that this could be one reason for the doubling of childhood asthma during these years.
2. We have also found an association between small fetal size and increased risk of asthma.
3. We have found that breast feeding has a short-lived effect on preventing allergies but this wears off over time as children become older.
4. Using soil information from colleagues we have found that early exposure to soil rich in silt is associated with increased asthma symptoms.

It is 25 years since we started recruiting the cohort. We last caught up with the children involved when they were 15 years old. This may have changed over the last decade! For the latest follow up we will use the same questions and tests as we used when the cohort and her members were 5, 10 and 15 years old. We hope that as many of the original cohort can take part as they approach their 25th birthday. We will be sending out questonnaires and doing breathing tests between March 2022 and June 2023, so we will be getting results from people who are aged between 23 and 25.

Our aims during this follow up study are:

1. To see if exposure to Vitamins D and E since birth are still associated with increased risk of wheeze and reduced lung function at 25 years of age.
2. To see if shorter fetal measurements will still be associated with increased risk of asthma at 25 years of age.

Our latest follow up is very similar to the previous times you have visited us at 5, 10 or 15 years of age.

We would like you to initially fill out an asthma and allergy questionnaire . We will write to you with details. The questionnaire can be done on paper and returned in the post or done on line.

If you would be willing we would then like you to visit us in the Health Sciences Building at Foresterhill. We can provide parking outside the bulding for you. The visit will last 30-40 minutes during which time we will check the following;

• Spirometry - This measures the amount (volume) and speed (flow) of air that can be inhaled and exhaled by your lungs. We do this by getting you to blow into a handheld tube connected to a computer.
• Nitric Oxide Measurement - This measures the amount of Nitric oxide in your exhaled breath. We all breathe this out but people with asthma have higher levels of this.
• Bloods - We are taking bloods to test for allergy.
• Height, weight, waist circumference - these are measured to see if there is any link for these too.
• Lean mass and total body fat - We can measure this with a simple device that simply needs you to take off your socks and shoes and stand on some weighing scales holding onto some handles. You will not feel a thing.
• Anxiety and Depression Questionnaire - we know that anxiety and depression are common in young adults. This questionnaire is totally optional, you don't have to fill it in. Research in other centres has found that anxiety and depression can be linked to things that happen in early life and to make the best use of the information we have collected in the 1990s we would like to see how the early life environment is linked to anxiety and depression in later life. Our research team includes a professional psychologist who can give support to those whose score suggest they have anxiety and depression.
• Saliva for DNA - we have already collected DNA in many of the "SEATON babies", but in a few individuals we either have never collected DNA or have used up what DNA we have in store. Therefore we will ask a few individuals to spit into a pot. We can get DNA from the cells in the spit. Again, this is totally optional.