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Lifestyle is more likely to affect a child’s body mass index than the weight of their mother before and during pregnancy say researchers who have found that a mother’s high BMI before and during pregnancy is not a major cause of high BMI in their offspring – indicating that childhood and teen obesity is more likely to be a result of lifestyle factors.
According to UK Government figures 9.9% of reception age children (age 4-5) are obese, with a further 13.1% overweight. At age 10-11 (year 6), 21.0% are obese and 14.1% overweight.
Research from the Centre for Longitudinal Studies (CLS) at the UCL Social Research Institute, published in December 2020, showed that one in five (21%) young people were obese at age 17, and a further one in seven (14%) were overweight.
Nature or nurture
Greater maternal BMI before or during pregnancy is known to be associated with higher BMI throughout childhood, but exactly how much a mother’s weight before or during pregnancy contributes to childhood obesity, or whether it is lifestyle and environmental factors that are responsible, remains unclear.
To investigate this question researchers from the University of Bristol (England) and Imperial College London used data from the “Children of the 90s” (also known as the Avon Longitudinal Study of Parents and Children), and data from the “Born in Bradford” longitudinal study.
For their study, published in BMC Medicine, researchers used Mendelian randomisation, measuring variation in genes to determine the effect of an exposure on an outcome, along with polygenic risk scores, to investigate if associations between before and during early pregnancy BMI, and a child’s BMI from birth to adolescence, are causal.
They looked at birth weight and BMI at age 1 and 4 years in both “Children of the 90s” and “Born in Bradford” participants, and then also BMI at age 10 and 15 years in just the Children of the 90s participants.
Since the effects being explored may differ by ethnicity the authors reported that they limited analyses to two ethnic groups – White European and South Asian.
Interventions targeting everyone needed
The researchers found that there was a moderate causal effect between maternal BMI and the birth weight of children, however they said they “found no strong evidence for a causal effect of maternal BMI on offspring adiposity beyond birth”.
Tom Bond, MSc, senior research associate at the University of Bristol, explained: “We found that if women are heavier at the start of pregnancy this isn’t a strong cause of their children being heavier as teenagers.”
The authors wrote that their results suggested that “higher maternal pre-/early-pregnancy BMI is not a key driver of higher adiposity in the next generation,” something that Mr. Bond said was “important to know”.
The authors concluded that their findings “support interventions that target the whole population for reducing overweight and obesity, rather than a specific focus on women of reproductive age”.
Mr. Bond pointed out that “it isn’t enough to just focus on women entering pregnancy.” However, “there is good evidence that maternal obesity causes other health problems for mothers and babies, so prospective mothers should still be encouraged and supported to maintain a healthy weight.”
A version of this article first appeared on Medscape UK.
Lifestyle is more likely to affect a child’s body mass index than the weight of their mother before and during pregnancy say researchers who have found that a mother’s high BMI before and during pregnancy is not a major cause of high BMI in their offspring – indicating that childhood and teen obesity is more likely to be a result of lifestyle factors.
According to UK Government figures 9.9% of reception age children (age 4-5) are obese, with a further 13.1% overweight. At age 10-11 (year 6), 21.0% are obese and 14.1% overweight.
Research from the Centre for Longitudinal Studies (CLS) at the UCL Social Research Institute, published in December 2020, showed that one in five (21%) young people were obese at age 17, and a further one in seven (14%) were overweight.
Nature or nurture
Greater maternal BMI before or during pregnancy is known to be associated with higher BMI throughout childhood, but exactly how much a mother’s weight before or during pregnancy contributes to childhood obesity, or whether it is lifestyle and environmental factors that are responsible, remains unclear.
To investigate this question researchers from the University of Bristol (England) and Imperial College London used data from the “Children of the 90s” (also known as the Avon Longitudinal Study of Parents and Children), and data from the “Born in Bradford” longitudinal study.
For their study, published in BMC Medicine, researchers used Mendelian randomisation, measuring variation in genes to determine the effect of an exposure on an outcome, along with polygenic risk scores, to investigate if associations between before and during early pregnancy BMI, and a child’s BMI from birth to adolescence, are causal.
They looked at birth weight and BMI at age 1 and 4 years in both “Children of the 90s” and “Born in Bradford” participants, and then also BMI at age 10 and 15 years in just the Children of the 90s participants.
Since the effects being explored may differ by ethnicity the authors reported that they limited analyses to two ethnic groups – White European and South Asian.
Interventions targeting everyone needed
The researchers found that there was a moderate causal effect between maternal BMI and the birth weight of children, however they said they “found no strong evidence for a causal effect of maternal BMI on offspring adiposity beyond birth”.
Tom Bond, MSc, senior research associate at the University of Bristol, explained: “We found that if women are heavier at the start of pregnancy this isn’t a strong cause of their children being heavier as teenagers.”
The authors wrote that their results suggested that “higher maternal pre-/early-pregnancy BMI is not a key driver of higher adiposity in the next generation,” something that Mr. Bond said was “important to know”.
The authors concluded that their findings “support interventions that target the whole population for reducing overweight and obesity, rather than a specific focus on women of reproductive age”.
Mr. Bond pointed out that “it isn’t enough to just focus on women entering pregnancy.” However, “there is good evidence that maternal obesity causes other health problems for mothers and babies, so prospective mothers should still be encouraged and supported to maintain a healthy weight.”
A version of this article first appeared on Medscape UK.
Lifestyle is more likely to affect a child’s body mass index than the weight of their mother before and during pregnancy say researchers who have found that a mother’s high BMI before and during pregnancy is not a major cause of high BMI in their offspring – indicating that childhood and teen obesity is more likely to be a result of lifestyle factors.
According to UK Government figures 9.9% of reception age children (age 4-5) are obese, with a further 13.1% overweight. At age 10-11 (year 6), 21.0% are obese and 14.1% overweight.
Research from the Centre for Longitudinal Studies (CLS) at the UCL Social Research Institute, published in December 2020, showed that one in five (21%) young people were obese at age 17, and a further one in seven (14%) were overweight.
Nature or nurture
Greater maternal BMI before or during pregnancy is known to be associated with higher BMI throughout childhood, but exactly how much a mother’s weight before or during pregnancy contributes to childhood obesity, or whether it is lifestyle and environmental factors that are responsible, remains unclear.
To investigate this question researchers from the University of Bristol (England) and Imperial College London used data from the “Children of the 90s” (also known as the Avon Longitudinal Study of Parents and Children), and data from the “Born in Bradford” longitudinal study.
For their study, published in BMC Medicine, researchers used Mendelian randomisation, measuring variation in genes to determine the effect of an exposure on an outcome, along with polygenic risk scores, to investigate if associations between before and during early pregnancy BMI, and a child’s BMI from birth to adolescence, are causal.
They looked at birth weight and BMI at age 1 and 4 years in both “Children of the 90s” and “Born in Bradford” participants, and then also BMI at age 10 and 15 years in just the Children of the 90s participants.
Since the effects being explored may differ by ethnicity the authors reported that they limited analyses to two ethnic groups – White European and South Asian.
Interventions targeting everyone needed
The researchers found that there was a moderate causal effect between maternal BMI and the birth weight of children, however they said they “found no strong evidence for a causal effect of maternal BMI on offspring adiposity beyond birth”.
Tom Bond, MSc, senior research associate at the University of Bristol, explained: “We found that if women are heavier at the start of pregnancy this isn’t a strong cause of their children being heavier as teenagers.”
The authors wrote that their results suggested that “higher maternal pre-/early-pregnancy BMI is not a key driver of higher adiposity in the next generation,” something that Mr. Bond said was “important to know”.
The authors concluded that their findings “support interventions that target the whole population for reducing overweight and obesity, rather than a specific focus on women of reproductive age”.
Mr. Bond pointed out that “it isn’t enough to just focus on women entering pregnancy.” However, “there is good evidence that maternal obesity causes other health problems for mothers and babies, so prospective mothers should still be encouraged and supported to maintain a healthy weight.”
A version of this article first appeared on Medscape UK.
FROM BMC MEDICINE