Tag Archives: Infant feeding

Wheezing: Can breastfeeding for longer make a difference?

Public health bodies put a lot of effort into encouraging mothers to breastfeed, and for good reasons. Successive studies have shown breastfeeding has a range of health benefits, including a lower risk of wheezing illnesses, which can be linked to asthma. But which of these illnesses are most likely to respond? Is a breastfed child less likely to develop wheezing after age five, or age seven, for instance? Or is the protective effect mainly measurable only in younger children? Professor Maria Quigley from the National Perinatal Epidemiology Unit at the University of Oxford, along with colleagues at Oxford and UCL, has been looking at how and when breastfeeding is associated with wheezing.

Asthma is the most common chronic condition affecting children and young people in the UK. It’s the most common reason why children are admitted to hospital, and sadly each year a few still die from the condition. According to the British Lung Foundation three children in every hundred under the age of five have been diagnosed with asthma at some point; and by age 10 that figure rises to one in 10.

There’s no cure, and so the priority for public health bodies has been to understand the disease better, to manage it better and to learn more about the factors that can protect us from it. One such protective factor is breastfeeding: two recent pieces of research have shown there is a lower risk among breastfed children, but that the effect is stronger among the very young – both for asthma and for wheezing, which has many causes and which does not necessarily develop into asthma.

Childhood wheezing can follow a variety of patterns – it can set in early but clear up before adulthood, for instance, or it can start later but continue into later life. Some wheezing will start in childhood and will continue.

Millennium Cohort Study

We wanted to look at how breastfeeding might affect these different types, so we used data from the Millennium Cohort Study, which has followed the lives of almost 19,000 children born in the UK between September 2000 and January 2002. Their parents were interviewed when they were 9 months old, and again when they were 3, 5, 7 and 11 years.

Our study focused on just over 10,000 children who were seen at all of those points and who were the product of single as opposed to multiple birth. Mothers were asked whether they had tried to breastfeed, and for how long their children had been breastfed.

Among our sample, seven out of 10 children had been breastfed: a little more than one in ten of the study sample for less than a week; a fifth for between one and three weeks, just over one in six for three to six months and around a quarter for six to nine months.

We found that at age 9 months, 6.5 per cent of children had a history of wheezing. At age 3 years, 19.5 per cent had such a history in the past year. As the children got older, though, this proportion decreased – 16 per cent at age five, 11.8 per cent at age seven and 11.4 per cent at age 11.

Overall, 37 per cent of children had suffered from wheezing at least once between 9 months and 11 years. A little under a fifth (18.8 per cent) had wheezing at younger age which cleared up when they got older, while 6.2 per cent had wheezing which started later and 11.8 per cent had persistent wheezing.

Feeding and wheezing

When we looked at the association between breastfeeding and wheezing, we found the children who had been breastfed for longest were less likely to suffer from wheezing.

But this effect lessened with time. For example, those breastfed for six to nine months were less likely to wheeze between the ages of nine months and five years, but by the age of 11 this group had no significant advantage over those who were breastfed for less time.

What does our study tell us about the relationship between breastfeeding and wheezing? The picture is a complex one. There are many causes of wheezing and of asthma, and those causes change over time. So in order to draw firm conclusions about cause and effect, we would need a much more complex dataset. It would be interesting, for instance, to look at clinical information on children’s allergies or their lung function.

But what we can say is that age matters – in order to understand how breastfeeding affects the development of wheezing during childhood, we must take a longer and more nuanced view.

Breastfeeding And Childhood Wheeze: Age-Specific Analyses and Longitudinal Wheezing Phenotypes as Complementary Approaches To The Analysis Of Cohort Data is research by Maria Quigley (University of Oxford), Claire Carson (University of Oxford) and Yvonne Kelly (UCL). It is published in the American Journal of Epidemiology.

An equal start: longitudinal evidence to support children’s healthy development

Using longitudinal evidence to support children’s healthy development and give them an equal start in life is the subject of our editor Yvonne Kelly’s keynote address at the Growing up in Ireland Annual Conference in Dublin today.

Her talk discusses findings from the most recent of the British ‘birth ‘ cohort studies – the Millennium Cohort Study that have so far informed policy development. They include work by researchers at the ESRC Centre for Lifecourse Studies where Yvonne is based on alcohol consumption during pregnancy, breastfeeding and the introduction of solid foods, the physical punishment of children , childhood obesity, reading to children in the early years, and sleep patterns throughout childhood.

She will also share work with the potential to inform future policy challenges such as young people’s drinking, social media use and mental health.

Ahead of her talk, she said:

“It is well established that what happens in the early years of life has long-lasting consequences for health and social success across the lifespan. Stark social inequalities in children’s health and development exist and emerge early in life. It is therefore crucial to identify potential tipping points and opportunities for intervention   during childhood with the potential to affect change and improve life chances.”

 

 

Giving children the best possible start – what matters most?

Child of our Time Editor Yvonne Kelly spoke to a 500-strong audience of politicians and professionals in Gothenburg recently on what matters when it comes to giving children the best possible start in life.

Yvonne was the keynote speaker at the conference hoping to identify the best strategies for making Gothenburg a more equal and socially sustainable city.

Yvonne, Professor of Lifecourse Epidemiology at the ESRC International Centre for Lifecourse Studies at UCL  explained which factors are most closely linked with a child’s health and well-being and presented her research findings on children’s verbal skills, behaviour, bedtimes, reading and obesity.

Putting a SPRING in the step of mums-to-be

Making sure that mums-to-be are in the best possible health is key to ensuring their baby gets the best possible start in life. But what sorts of things can help them achieve that? In this episode of the Child of our Time Podcast, Professor Hazel Inskip from the MRC Lifecourse Epidemiology Unit at the University of Southampton, talks about an ongoing trial making use of healthy conversations and Vitamin D supplements to try to improve the diet of just pregnant women.

Photo credit: Pregnant, Frank de Kleine

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Sugar-coating the childhood obesity problem

Child obesity figures appear to be on the rise again, causing much concern after earlier signs they had levelled off.  The proportion of  10- and 11-year-olds who were obese in 2015-16 was 19.8 percent, up 0.7 percent on the year before. There was a rise of 0.2 percent among four- and five-year-olds. The announcement comes as researchers at the ESRC International Centre for Lifecourse Studies at UCL have been looking in detail at how and when children become overweight. The team has also been asking whether children who are overweight are more likely to go on to smoke and drink alcohol and if their mental health suffers as they become adolescents. Yvonne Kelly explains the research findings, and considers their implications for the Government’s recent strategy for tackling the childhood obesity epidemic.

The Government’s much-awaited and much-debated childhood obesity strategy was published in August. In the end, it was less comprehensive than had been anticipated, less draconian too. It focuses on two things – reducing sugar consumption and increasing physical activity. But will it be effective in reversing this worrying obesity trend among our children?

It’s fair to say we don’t fully understand what things influence whether, when and why a child might become overweight. Research to date has shown three distinct weight pathways for children: a healthy BMI throughout childhood; becoming overweight during childhood and being overweight/obese throughout childhood.

Previous research has also shown that the child’s mother’s weight, smoking in pregnancy, mental health and other social and economic factors have some link to childhood obesity. But the evidence is far from complete and, where a child’s own mental health is concerned, it’s not at all clear which way the association works.

To try to get a clearer picture of all these things, our research looked at the BMI paths of the participants in the Millennium Cohort Study, which has tracked the lives of nearly 20,000 children born between 2000-2002. We used data collected at birth, 9 months, age 3, 5, 7 and 11.

Once we had established who was on which BMI path, we were able to look at what factors were at play in their lives and to see whether a tendency to overweight and obesity was an indication that a child would go on to face mental health difficulties in early adolescence or start smoking and drinking.

Four pathways to obesity

The BMI data for the 17,000 children we were able to look at for our study showed four distinct groups of children. More than 80 per cent of them stayed on an average non-overweight path throughout their childhood – we call it the ‘stable’ path. There was a small group (0.6 percent) of children who were obese at age 3 but were then in the stable group by age 7. We call them the the ‘decreasing’ group. There was a ‘moderate increasing group’ (13.1 percent) where children were not overweight at age 3 but whose BMIs increased throughout childhood into the overweight (but not obese) range. Finally we had a ‘high increasing’ group of children (2.5 percent) who were obese at age 3 and whose BMIs continued to increase.

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Girls were 30 percent more likely to be in the ‘moderate increasing’ group than boys and were half as likely to be on the ‘decreasing’ path. Indian, Pakistani and Black African children were up to two times more likely to be on the ‘moderate increasing’ path whilst Pakistani, Black Caribbean and Black African children were up to three times more likely to belong to the ‘high increasing’ group.

The wealthiest children were least likely to be in the ‘moderate increasing’ BMI group and children of mums who smoked during pregnancy were up to two times as likely to belong to increasing BMI groups. Children with overweight mums were most likely to be on the moderate and high increasing paths.

Children on the moderate and high increasing paths were less likely to have regular family routines – they were more likely to skip breakfast or have non-regular bedtime schedules. Interestingly, however, no strong links emerged with some of the things more readily linked with childhood obesity such as sugary drinks and snacks, watching TV and lack of physical activity such as sports, the main focus of the newly published childhood obesity strategy.

Overweight factors

So it seems quite a large range of factors influence the likelihood of a child becoming overweight or obese over the first decade of their life. On top of this, being overweight or obese would also seem to point to a less happy and fulfilling early adolescence and a tendency to explore risky behaviours like smoking and drinking.

Although our research did not show a clear link with sugary drinks and snacks, there are nevertheless some compelling arguments for reducing the sugar intake of our children. These are not only related to problems of obesity, but to wider issues including the major issue of tooth decay and associated emergency hospital admissions. There is also increasing evidence of the ‘addictive’ nature of sugar with research suggesting that it stimulates a sort of ‘reward path’ in certain centres of the brain meaning that the more we have the more we want. It has been shown that people who reduce their sugar intake tend to crave it less.

Where sugar taxes have been introduced in other countries (Mexico, France, Denmark, South Africa amongst others), the intervention has been shown to help reduce the consumption of sugary drinks. As yet, there is no evidence that it helps reduce BMI and tackle obesity, but it’s argued it will take time for us to see an effect on whole populations.

Disadvantaged families

It is hard to predict how much impact the voluntary rather than mandatory reduction in sugar content of drinks and snacks agreed in the strategy will have. As for the sugar tax that will be introduced in two years’ time, there remain concerns that disadvantaged families more likely to purchase and consume sugary goods than their better off counterparts will be hardest hit. Policy makers will need to think hard about how any negative consequences of this might be counteracted.

Our research shows clearly that when it comes to the likelihood of a child becoming overweight or obese in the first decade of their life, there are many more influences than just sugar. Those influences are at play in families even before our children are born.

Helping pregnant women to stop smoking and maintain a healthy weight, making sure all young children have healthy eating and sleeping routines would seem to be key, together with targeted support for the ethnic and social groups identified as being most at risk.

Further information and resources

BMI development and early adolescent psychosocial well-being: UK Millennium Cohort Study is research by Yvonne Kelly, Praveetha Patalay, Scott Montgomery, and Amanda Sacker. The work, published in Pediatrics, is funded by the Economic and Social Research Council.

Media coverage

Photo credit: Kim Stromstad

Born in Bradford

Born in Bradford is a fascinating child health development project following the lives of thousands of children in the city. It hopes to find out more about the causes of childhood illness by studying children from all cultures and backgrounds as their lives unfold.

In this Child of our Time Podcast episode, one of the project’s lead researchers, Professor Kate Pickett from the University of York, explains more about the study, what’s in it that researchers can use, what  it’s found so far and what we can expect to come out of it in the future.

Photo credit: Tim Green

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Ethnicity, birthweight and growth in early childhood

Birthweight varies according to ethnic group but height at the age of five does not. Why might that be? Does it tell us anything about the lives of second and third generation immigrants? And does it offer any useful guidance to health professionals hoping to target disadvantaged groups? Professor Yvonne Kelly outlines recent research with colleagues at the ESRC International Centre for Lifecourse Studies looking at differences in birthweight and early growth between ethnic groups.

Birthweight is important. There is a large body of work that suggests links between low birthweight and the development of chronic disease. Height at the age of five is a less straightforward indicator but still an important measure. The relationship between the two is important as well. Rapid post-natal growth may also have a role in later disease risk, and any correlation may tell us something about the lives of people born in the UK to parents born elsewhere.

Earlier research shows that babies born to South Asian and Black mothers weigh up to 300g less than those with White mothers. They are also up to two and a half times more likely than their White counterparts to have low birthweight.

Our study made use of the rich information available in the Millennium Cohort Study and enabled us to drill down further into ethnic differences. We were able to look at White, Indian, Pakistani, Bangladeshi, Black Caribbean and Black African groups.

These, of course, are groups that have very different migration histories. The Black Caribbeans and Indians mainly migrated to the UK in the 1950s and 1960s. The Pakistanis arrived in the 1960s and 1970s, the Bangladeshis in the 1980s and the Black Africans in the 1990s.

Social v biological

If you accept that ethnicity is a social not a biological construct, these variations must be the result of factors that are not intrinsic to the group but tend to go with membership. Relevant factors are likely to be either socioeconomic or maternal.

So, if one group tends to have higher incomes and higher levels of educational attainment, it is likely to have fewer babies with low birthweight. Similarly, if mothers within one group are less likely to smoke they too are likely to have heavier babies.

Because our research compared data on birthweight to those on ethnicity, socioeconomic status and maternal characteristics, it was possible to identify which were most closely associated.

The results suggest that socioeconomic factors are important in explaining birthweight differences in Black Caribbean, Black African, Bangladeshi and Pakistani infants. Maternal characteristics are important in explaining birthweight differences in Indian and Bangladeshi groups. Clearly, both must operate to some extent in all cases.

Our study identifies the dominant factor for each ethnic group and recommends policy-makers pay attention to the different socioeconomic and culturally related profiles of ethnic minority groups when devising policies aimed at reducing inequalities in birthweight.

A question of height

One key maternal characteristic identified was height. Mothers from the Indian, Pakistani and Bangladeshi groups were on average 8cm shorter than White mothers. We speculate that it might take several generations for individuals within ethnic groups to reach their height potential.

And it could be that increases in maternal height do not happen so much for the first couple of migrant generations due to the ‘accumulated effects of disadvantage, including racism, discrimination and poverty that are disproportionately experienced by migrants’. That idea was put to the test in a second study also using MCS data.

The primary aim of this research was to investigate ethnic differences in height at 5 years of age. The same ethnic groups were used. Again, the sample was large and broadly representative of the whole UK.

Playing catch up

In contrast to the findings on birthweight, Indian, Pakistani, Black Caribbean and Black African children were taller than White children at age 5. Bangladeshi children were the same as White children. Birthweight was not entirely irrelevant. It was a weak to moderate predictor of height in White, Pakistani, Bangladeshi and African children.

All the measured variables favoured the White group over all ethnic minorities. This is consistent with the suggestion floated towards the end of the first study that what is happening is that a generation is ‘catching up’, earlier generations having been previously thwarted by such factors as poor nutrition in underdeveloped home countries.

Saying that, catch-up growth is likely to explain only a part of the ethnic height differences identified and further research is important here. It is also important to note that taller children are more inclined to obesity and so the height advantage of ethnic minority children might not translate into a health advantage in adulthood.

The links between ethnicity, birthweight and height in childhood are not, then, straightforward or by any means fully understood. It is clear that outcomes associated with different groups are the result of social and not biological characteristics.

The length of time a group has been established in the UK also appears to play a part with at least some suggestion of a generational ‘catch-up’ effect. Though there may be plenty of inequality left to address, that does at least suggest things are moving in the right direction.

Further information

Why does birthweight vary among ethnic groups in the UK? Findings from the Millennium Cohort Study is research by Yvonne Kelly, Lidia Panico, Mel Bartley, Michael Marmot, James Nazroo and Amanda Sacker and is published in the Journal of Public Health.

Ethnic differences in growth in early childhood: an investigation of two potential mechanisms is research by Amanda Sacker and Yvonne Kelly and is published in the European Journal of Public Health.

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[1] Ethnic differences in growth in early childhood: an investigation of two potential mechanisms. A. Sacker, Y. Kelly

Breastfeeding and ethnicity

Helping more mothers breastfeed is a policy goal shared by many governments. Advocates argue that breastfeeding has a positive impact on a child’s physical, cognitive and behavioural development. Because of overlaps with other factors such as a mother’s social class or education, it is hard to measure precisely the degree to which breastfeeding alone benefits a child, but most policy-makers accept there is a benefit and want to know how to encourage more mothers to start it and stick with it. The incidence of breastfeeding varies significantly between women with different ethnic backgrounds and in different ways in the UK and US. Professor Yvonne Kelly from the ESRC International Centre for Lifecourse Studies at UCL asks if there are clues here as to how best to encourage women from different backgrounds to breastfeed their children.

The UK has one of the lowest breastfeeding rates in the world, although according to the NHS Infant Feeding Survey of 2010, the proportion of babies breastfed at birth is 81%, up from 76% in 2005. At three months, the proportion of mothers breastfeeding exclusively is 17%. At six months, the figure is just 1% and that has not changed since 2005.

The same survey found that breastfeeding was most common among mothers who were: aged 30 or over, from minority ethnic groups, left education aged over 18, in managerial and professional occupations and living in the least deprived areas.

The fact that younger, less educated, less well-off women are less likely to breastfeed is not surprising. Indeed, encouraging breastfeeding is at least partly about reducing inherited disadvantage. What may be less obvious (to the majority population, at least) is that ethnicity appears also to be a significant factor.

Millennium Cohort Study

When we looked at the data in the Millennium Cohort Study, which has been tracking the lives of some 20,000 children born at that time, we saw that well over 90% of Black African and Black Caribbean mothers at least started breast feeding.

The figure was over 85% for Indian and Bangladeshi mothers, 75% for Pakistani mothers and 67% for white mothers. Even after adjusting for demographic, economic and psychosocial factors, the difference remains significant.

At three months, with a range of factors considered, Black African mothers are more than 5 times more likely than white mothers to have started and continued to breastfeed. Clearly, if we understood why Black mothers were more likely to breast feed than white mothers we might have a better understanding of how to encourage all mothers to breast feed.

US comparison

An important part of our efforts to gain a clearer picture was to look for similar patterns in similar countries. So we did a comparison with the United States, where the overall rates for breastfeeding are very similar to the UK, as are the links between breastfeeding and socioeconomic status. Not at all similar, however, are the links between ethnicity and breastfeeding.

In the US, the highest rate, according to the National Immunization Survey in 2002, was among Hispanic mothers, at 80%. 72% of white mothers initiated breastfeeding. Only 51% of non-Hispanic black mothers did. So, in the UK black mothers are the most likely to breastfeed. In the US, they are the least likely.

Why the difference, given that usually, health problems suffered disproportionately by black Caribbean people in the UK affect black Americans similarly. Is there a mistake somewhere? We consider the possibility of recall bias in light of the fact that data were collected when the children were 9 months old.

It does seem reasonable to suspect mothers might want to believe they did more breastfeeding than was actually the case. But there is no obvious reason why that bias should apply differently in the UK and US. As the study suggests, the contrasting findings in the UK and US raise important wider questions about the nature of ethnic disadvantage.

One possible answer is that differences in breastfeeding reflect strength of cultural tradition and degree of “integration”. This, of course, can vary for similar ethnic groups in different “host” communities. The important thing is not the ethnic group itself, but the relationship between it and the rest of society.

Dominant cultural practices

Our study found that those who spoke only English at home were less likely to breastfeed. That raises the concern that as incoming groups adopt dominant cultural practices, their tendency to breastfeed will reduce. Cultural factors certainly merit further investigation, given that the only thing we considered in this study was whether English was the main language spoken at home.

Black people in the UK and black people in the US have different histories and, therefore, different identities. There are differences, too, in their “host” communities. In this instance, the very different health systems could be particularly relevant. Maybe future research should concentrate on this relationship rather than the behaviour of groups defined by characteristics that appear to have only secondary significance.

Those responsible for developing and implementing policies aimed at increasing breastfeeding rates in this area would certainly be advised to pay close attention to the different social, economic and cultural profiles of all ethnic groups.

Racial/ethnic differences in breastfeeding initiation and continuation in the United kingdom and comparison with findings in the United States  is research by Yvonne Kelly, Richard Watt and James Nazroo and is published in Pediatrics, Official Journal of the American Academy of Pediatrics..

Photo credit: US Breastfeeding Committee

 

Breastfeeding – to a schedule or on demand?

Mums-to-be are frequently advised in baby books that feeding to a schedule is best for their  child. But what does the evidence tell us when it comes to the different approaches and what might that mean for parents, practitioners and policy makers?

Dr Maria Iacovou from the University of Cambridge presents recent evidence breastfeeding research at an ESRC Centre for Lifecourse Studies Policy Seminar.

Photo credit: clogsilk

Related links

Scheduled versus demand feeding of infants: How do different feeding modes affect sleeping patterns in older childhood, and do they affect the risk of obesity, ESRC International Centre for Lifecourse Studies Occasional Paper 13.1

Breastfeeding and intergenerational social mobility, what are the mechanisms? A propensity score matching analysis of two population based cohort studies, Archives of Disease in Childhood, 2013.

Infant feeding: the effects of scheduled vs. on-demand feeding on mothers’ wellbeing and children’s cognitive development, European Journal of Public Health, 2013, 23(1) pp 13-19.

The Effect of Breastfeeding on Children’s Cognitive and Non-cognitive Abilities, Labour Economics 19, 2012.

The effects of breastfeeding on children, mothers and employers, Research project information, Institute for Social and Economic Research, University of Essex.