Firstborns are [more likely to be] Fatter, Who Would Have Thought?

[The Anti-Targ]

http://www.nzherald.co.nz/lifestyle/news/article.cfm?c_id=6&objectid=11503738

 

40% more likely to be obese compared to younger sisters.

 

This is a study about women specifically, but a similar study into firstborn men found the same pattern.

 

Interesting observations:

 

More single child families means proportionally more people are "firstborns", which could be a contributing factor to growing obesity.

 

Obesity isn't the only health risk associated with being firstborn.

 

Interesting hypothesis about the reason:

'Researchers have yet to find the reason for the differences between firstborns and those born later, but Professor Cutfield proposes that it is due to differences in the blood supply to the placenta.

 

"In a first pregnancy, the blood vessels to the placenta are narrower. This reduces the nutrient supply, thus reprogramming the regulation of fat and glucose, so that in later life the firstborn is at risk of storing more fat and having insulin that works less effectively," Professor Cutfield said.'

 

If that's a large part of the reason for this pattern, then it obviously means a lot of nutritional research and education needs to go in to first-time pregnancies. If the blood supply to the foetus is lower in first pregnancies compared to subsequent pregnancies then there need to be more nutrients in the blood. I'm a bit leary about the idea of developing a drug that could increase blood vessel size, but that could also be a possibility. Pre-pregnancy health and nutrition could also play a role in the development of the placenta. Could placenta development be slightly impared with age? Is the pattern of first pregnancies occurring at older ages compared to past generations another possible factor?

[Maya Mia]

Well, as the first born of 4, I am definitely heftier than my siblings, while being the shortest of them.  Of course, my ancedotal experience proves this theory   :)

 

But on the other hand, my firstborn is the smallest of my three, in both weight and height.  My firstborn is 24, and my youngest is 15, so that ancedotal experience disproves this theory  :)

'

Edit:  add my childen info.

[Iskaral Pust]

That's an interesting study. Most prior studies on birth order were about personality characteristics and socioeconomic attainment -- first borns tend to be more responsible and have higher average lifetime earnings.

I wonder if associated personality factors like stress contribute to the obesity.

To add a meaningless data point, I'm a first born and definitely the most responsible and career oriented of my siblings, but also the slimmest.

[Ormond]

Unfortunately the journalistic report here does not make it clear if only children were included among the "firstborns" in this study's data. But one CANNOT assume that this would affect only children without separate data on them. Only children are both lastborns and firstborns, and psychologically they don't grow up with the same family pressures and stresses that firstborns with younger siblings do. 

 

IF the scientist quoted about the "first pregnancy" theory is correct, only children would be equally at risk to firstborns with younger siblings. But that idea as presented in the article seems to be speculation to me, and you can't say this study gives evidence for it unless you actually can separate out the data from only children and firstborns with siblings to see if they are similar in terms of obesity rates. 

[Lily Valley]

You also need to include lifetime study of stress hormones.

[Stego]

Obesity is based on behavior and little else. 

[Littlefingers In The Air]

What influences the behavior that leads to obesity, though? Keeping in mind that correlation is not causation, I do admit I find the OP interesting.

[JonSnow4President]

Obesity is based on behavior and little else. 

For most cases, this is somewhat true.  Of course, at my healthiest (roughly 195 pounds at 6'2," ribs showing until 225), I've always had a higher % of body fat than either of my brothers (I'm firstborn), even when the 3 of us performed the exact same workout every day, with both of them eating (slightly) more of the same thing than me, with the same routine outside of swimming.  

 

Now, this isn't to say that my current situation (grossly obese, 350 pounds at 6'3") is the result of me being firstborn by any stretch.  That's a stretch of continuing to eat like a swimmer well after I stopped the swimming workout, living near and all you can eat dining hall with chicken fried steak sandwiches, and a general lack of nutrition.  

 

But even if all of the above was perfectly equal, I will always have a higher percentage of body fat than my brothers among equal circumstances.  So it's not all behavior, although behavior is by far the biggest factor.

[The Anti-Targ]

Unfortunately the journalistic report here does not make it clear if only children were included among the "firstborns" in this study's data. But one CANNOT assume that this would affect only children without separate data on them. Only children are both lastborns and firstborns, and psychologically they don't grow up with the same family pressures and stresses that firstborns with younger siblings do. 

 

IF the scientist quoted about the "first pregnancy" theory is correct, only children would be equally at risk to firstborns with younger siblings. But that idea as presented in the article seems to be speculation to me, and you can't say this study gives evidence for it unless you actually can separate out the data from only children and firstborns with siblings to see if they are similar in terms of obesity rates. 

The placental bloodflow thing is only presented as an hypothesis, which therefore means there needs to be more study undertaken to prove or disprove the hypothesis. You make an observation, you come up with possible reasons for the observation, you pick the reasons you think most likely then you test the hypothesis to see if it's right. With the placental blood flow hypothesis they're basically only at step 2 in that list, or maybe step 3, if they think the placental blood flow is the strongest possibility, which is why it's mentioned in the article.

 

The study/article does suggest that increased obesity rates in the population could be related to increased one child families. Given that a one child family with a fat child has 100% of children being fat, whereas a 2 child family with one fat child only has 50% of children being fat.

 

In my family we have an example that aligns with this observation and an example that counters it. My older son has a greater tendancy to become fat than my younger son. Even though my older son goes to the gym 4 times a week and my younger son does less exercise (Kung Fu 2 times per week) he still has higher body fat. My nephew-in-law is short and skinny and is the oldest in his family with a younger sister who is taller and beefier (not fat by any stretch but definitely with a much higher body fat content than her brother, some of that is going to be physiology difference related to sex of course).

 

It is also the case that my older son has a larger natural appetite than my younger son. Appetite, mental illness notwithstanding, is physiologically driven. People have essentially inbuilt subconscious switches that tell them when they're full and they no longer feel hungry, and this has nothing to do with conscious self control. Pre-natal nutrition could potentially affect the way your hunger switch works. Being rather starved of nutrition in the womb could lead to feelings of hunger remaining long after you have eaten sufficient to meet your daily nutritional needs, which might be a life-long thing.

[The Anti-Targ]

For most cases, this is somewhat true.  Of course, at my healthiest (roughly 195 pounds at 6'2," ribs showing until 225), I've always had a higher % of body fat than either of my brothers (I'm firstborn), even when the 3 of us performed the exact same workout every day, with both of them eating (slightly) more of the same thing than me, with the same routine outside of swimming.  

 

Now, this isn't to say that my current situation (grossly obese, 350 pounds at 6'3") is the result of me being firstborn by any stretch.  That's a stretch of continuing to eat like a swimmer well after I stopped the swimming workout, living near and all you can eat dining hall with chicken fried steak sandwiches, and a general lack of nutrition.  

 

But even if all of the above was perfectly equal, I will always have a higher percentage of body fat than my brothers among equal circumstances.  So it's not all behavior, although behavior is by far the biggest factor.

Well it is always about behaviour at the most basic, simplistic and rather ignorant level. If you basically starved yourself you would be skinny, eventually, and be skinnier than your siblings. It's the implication that it's all about choosing to lead a gluttonous, lazy lifestyle that is the sole reason why everyone who is fat is fat that is very harmful both at a personal level but also at a scientific level.

 

If you think it's just about choice, then you won't do research to see if there are deeper factors, and thus you won't make discoveries that can help to both treat and prevent obesity. If it is true that narrow blood vessels in the placenta increases the risk of a firstborn to be fat, then you can start looking for preventative mitigations to reduce that risk. If you just say "oh it's their choice" then you don't look for ways people can do things to give the child a better start out of the gate, as it were.

 

It would also be interesting to see what the effect of the degree of morning sickness through pregnancy would be on obesity in offpsring. If pre-natal nutrition is a risk factor, then a woman who suffers significant morning sickness and who therefore has fairly poor nutrition during pregnancy can be more closely nutritionally managed to make sure foetal nutrition is minimally affected.

 

It may also be that there are things that happen at specific times during pregnancy, which coincide with development of specific organs, or specific parts of the brain, that can have an effect. Sit may not be what happens over the entire course of a pregnancy, it might be something that happens with one or 2 days at a specific stage of the pregnancy.

 

In veterinary science there is a very well known phenomenon regarding cyclopian sheep. If a ewe eats the plant Veratrum californicum on the 14th day of pregnancy the lamb will be born as a cyclops, it won't happen if the ewe eats this plant on the 13th or 15th day of pregnancy and not the 14th day. If a ewe eats this same plant on the 17th and 18th days of pregnancy the lamb will be born with paralysed hind legs. this of course is a severe example associated with a toxic plant. But other nutritional influences could have subtler effects that are far harder to identify. It is also much easier to find single causes related to obvious physical traits than to find the principle causes of behavioural traits.

[Ormond]

The placental bloodflow thing is only presented as an hypothesis, which therefore means there needs to be more study undertaken to prove or disprove the hypothesis. You make an observation, you come up with possible reasons for the observation, you pick the reasons you think most likely then you test the hypothesis to see if it's right. With the placental blood flow hypothesis they're basically only at step 2 in that list, or maybe step 3, if they think the placental blood flow is the strongest possibility, which is why it's mentioned in the article.

 

The study/article does suggest that increased obesity rates in the population could be related to increased one child families. Given that a one child family with a fat child has 100% of children being fat, whereas a 2 child family with one fat child only has 50% of children being fat.

 

 

 

The fact that the placental bloodflow idea is just a hypothesis was precisely my point. 

 

As the birth rate has decreased, the % of 2 child families has gone up as well as the % of only children. You still cannot say that the increase in obesity is accounted for by an increase in only children UNLESS you do have actual data on only children by themselves, comparing them to firstborns in families of two, that show that only children do have at least as high a rate of obesity as firstborns in families of two. It is possible that the original research study does contain such data, but that is simply not given in the journalistic report of it we have here. 

[Glaurung]

This may not be PC, but couldn't it have to do with the possibilities that children who are first born don't have to share as often as others?  I was the youngest of 4 kids and my parents could barely afford to put food on the table.  We had to share with our siblings.  My oldest brother though has never gotten rid of the chub he built up when he was young.  Although he slimmed up quite a bit later in his life, he never completely recovered from the 10 + years where he was either the only child or 1 of only 2, and my parents weren't struggling so much.  He was spoiled when he was young.  Cookies, cake, soda, etc.  The things I never had because we couldn't afford them, he always had access to when he was young.  This also I think sets eating habits.  He has an affection for sugar that I've never had, and I can't help but think that the fact that he always had plenty of it when he was younger may have contributed to this.  

 

Single children are more likely to be spoiled.  They have more attention devoted to them, as well as more resources, which include food.  I think this would lead to an increased chance of childhood obesity.  It can also lead to behavioral patterns that other children are less likely to form, so it can affect them later in life too. If you've been obese when you're younger, you're more likely to be obese later in life as well. 

[JonSnow4President]

This may not be PC, but couldn't it have to do with the possibilities that children who are first born don't have to share as often as others?  I was the youngest of 4 kids and my parents could barely afford to put food on the table.  We had to share with our siblings.  My oldest brother though has never gotten rid of the chub he built up when he was young.  Although he slimmed up quite a bit later in his life, he never completely recovered from the 10 + years where he was either the only child or 1 of only 2, and my parents weren't struggling so much.  He was spoiled when he was young.  Cookies, cake, soda, etc.  The things I never had because we couldn't afford them, he always had access to when he was young.  This also I think sets eating habits.  He has an affection for sugar that I've never had, and I can't help but think that the fact that he always had plenty of it when he was younger may have contributed to this.  

 

Single children are more likely to be spoiled.  They have more attention devoted to them, as well as more resources, which include food.  I think this would lead to an increased chance of childhood obesity.  It can also lead to behavioral patterns that other children are less likely to form, so it can affect them later in life too. If you've been obese when you're younger, you're more likely to be obese later in life as well. 

Once again, this is anecdotal, but the oldest in our family (me, who was only an only child for 366 days) was always the one who took care to make sure that everyone had their fair share.  Meanwhile, I'm overweight (which started as a result of my college lifestyle), while the brothers who don't think twice about other people's portions are skinny.  

 

It could be.  But for what it's worth (next to nothing), the only anecdotal evidence I have on the matter suggests no.  The other older siblings in the family never exhibited selfish behavior either, and among all same sex siblings, the oldest is significantly the heaviest (the one exception being an older sister and younger brother.  Neither are overweight).

[Gneisenau]

Do parents get richers as time goes on ? One factor could be the oldest born was born in a poorer family, and their have been studies about wealth and obesity, but by the time the next kids are born the parents are richer and can get better foods.

[Nas!]

My older (eldest) brother is way fatter AND way richer than me.

Also, he has brown eyes, likes baseball and is narcoleptic.

[Jo498]

I might be naive, but I think that literally not having enough food on the table for the younger siblings seems very rare in the last few decades in the Western world. And even if that is the case I would expect that often parents or older siblings make sure that the youngsters are well fed.

I have 4 younger siblings (born 70s/80s) and we were all quite skinny until mid-twenties or so. Now, in my early forties I am probably about 5-8 kg too heavy and my youngest sister (31) is also not slim and could lose a few pounds but neither is grossly overweight. The three middle ones (35-41) are all still rather skinny/slim, but two of them do a lot of sports. With my younger brother it must be genetic. He is too lazy for sports but often also too lazy or busy to eat properly.

[Theda Baratheon]

Ha ha ha well I was 5 weeks early and my younger sister was a giant lump of a baby! Not as big as my grampa tho who was A STONE (!!!!)
I was 4 odd pounds as 5 weeks premature though so i probably would have been a pretty big baby if i'd been born on time haha

[Felguy]

Obesity is based on behavior and little else. 

Yes and no.

 

There comes a lot more into play than you think. Especially something of recent times: Gut flora.

 

But, yes, eat right and limit your calorie intake accordingly and you should lose weight.

[Glaurung]

Once again, this is anecdotal, but the oldest in our family (me, who was only an only child for 366 days) was always the one who took care to make sure that everyone had their fair share.  Meanwhile, I'm overweight (which started as a result of my college lifestyle), while the brothers who don't think twice about other people's portions are skinny.  

 

It could be.  But for what it's worth (next to nothing), the only anecdotal evidence I have on the matter suggests no.  The other older siblings in the family never exhibited selfish behavior either, and among all same sex siblings, the oldest is significantly the heaviest (the one exception being an older sister and younger brother.  Neither are overweight).

 

Your experience is a one-off experience though.  I don't think it is something that would be true for all families, or even most.  But if you take a sample size across thousands of families, I think it would show a pattern.  Sometimes the oldest is the skinniest.  

 

It could also be that you put your weight on in college.  Once you put weight on for the first time, it is more likely that you will keep it on later in life.  I know a lot of people that never had a weight issue, but then went through a short period where they gained weight due to some changes they experienced, and they never lose that weight, even if they don't add to it.   

[Glaurung]

I might be naive, but I think that literally not having enough food on the table for the younger siblings seems very rare in the last few decades in the Western world. And even if that is the case I would expect that often parents or older siblings make sure that the youngsters are well fed.

I have 4 younger siblings (born 70s/80s) and we were all quite skinny until mid-twenties or so. Now, in my early forties I am probably about 5-8 kg too heavy and my youngest sister (31) is also not slim and could lose a few pounds but neither is grossly overweight. The three middle ones (35-41) are all still rather skinny/slim, but two of them do a lot of sports. With my younger brother it must be genetic. He is too lazy for sports but often also too lazy or busy to eat properly.

 

I'm not talking about not having enough food.  Just no excess food.  You eat what you need.  Also, when you are in a poor family you might not have access to deserts and sugary drinks.  They might be seen as a commodity.  

 

It could also have to do with the idea that people mature as they get older.  When they're younger and only have one child, they might not be used to feeding a child and might not know how to properly provide a healthy diet to them.  Where as by the time they have multiple children, they might have a better idea of a child's healthcare needs.  It could also be that often times if the firstborn becomes obese, they realize what they did to contribute to it and the parents are the ones that change their own behavior so they don't repeat this with the other children.  It might be too late for the first born at that point, but the younger children could benefit from parents who have learned valuable dietary lessons.

 

I also think it just has to do with the fact that an only child(and all first borns are only children for a while) are more likely to be given whatever they want, and often times what they want is pizza, ice cream, soda, etc.  I think even parents who have multiple children are more likely to spoil the oldest, because it is hard to say no to the first born...you don't like hearing your child cry.  And while you never love hearing your children cry, by the time you have several of them, you're just used to it and less likely to give in to their demands. This isn't a knock on only children or first borns, and I'm not trying to criticize parents.  Many aren't guilty of this, perhaps most aren't.  But some are, and if you are sampling large enough of a population size, I think the pattern will show these results.