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Growth pattern from birth to adulthood in African pygmies of known age.

Rozzi FV, Koudou Y, Froment A, Le Bouc Y, Botton J - Nat Commun (2015)

Bottom Line: Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life.It then more or less follows the standard pattern, with a growth spurt at adolescence.Their life history variables do not allow the Baka to be distinguished from other populations.

View Article: PubMed Central - PubMed

Affiliation: UPR 2147 CNRS, 44 rue de l'Amiral Mouchez, 75014 Paris, France.

ABSTRACT
The African pygmy phenotype stems from genetic foundations and is considered to be the product of a disturbance in the growth hormone-insulin-like growth factor (GH-IGF) axis. However, when and how the pygmy phenotype is acquired during growth remains unknown. Here we describe growth patterns in Baka pygmies based on two longitudinal studies of individuals of known age, from the time of birth to the age of 25 years. Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life. It then more or less follows the standard pattern, with a growth spurt at adolescence. Their life history variables do not allow the Baka to be distinguished from other populations. Therefore, the pygmy phenotype in the Baka is the result of a change in growth that occurs during infancy, which differentiates them from East African pygmies revealing convergent evolution.

No MeSH data available.


Related in: MedlinePlus

Spaghetti plots of individual Sempe32-based Z-scores of height and weight over time.Each colour line represents one subject. The plain black line represents the average trend in the population, thanks to a LOESS-based approach. The flexibility of the LOESS regression function was control through the smoothing parameter ‘span' set at 0.3 for weight and 0.8 for height. (a,b) Z-score of weight at birth in boys and girls from the Baka population is close to zero, which means that weight at birth is not very different from the Sempe reference one. Then, the mean Z-score decreases rapidly until 2 or 3 years and remained around −2 until the end of follow-up in girls and until 15 in boys where mean Z-score seems to decrease again. (c,d) Mean Z-score of height (available from 2 years), is already at about −3 at this age and fluctuates around this value along the follow-up. In boys, as for weight, height difference seems to increase a little from 15 years.
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f3: Spaghetti plots of individual Sempe32-based Z-scores of height and weight over time.Each colour line represents one subject. The plain black line represents the average trend in the population, thanks to a LOESS-based approach. The flexibility of the LOESS regression function was control through the smoothing parameter ‘span' set at 0.3 for weight and 0.8 for height. (a,b) Z-score of weight at birth in boys and girls from the Baka population is close to zero, which means that weight at birth is not very different from the Sempe reference one. Then, the mean Z-score decreases rapidly until 2 or 3 years and remained around −2 until the end of follow-up in girls and until 15 in boys where mean Z-score seems to decrease again. (c,d) Mean Z-score of height (available from 2 years), is already at about −3 at this age and fluctuates around this value along the follow-up. In boys, as for weight, height difference seems to increase a little from 15 years.

Mentions: The plot of individual Sempe32-based Z-scores of height and weight over time (Fig. 3) shows that Baka birth with a weight close to standard values and decrease markedly during the first month of life becoming around −2 Z-scores from 2 to 3 years until adulthood in girls; in boys, difference seems to increases from 15 years of age. Data on height in Baka for earliest years of post-natal life are scarce and does not allow to obtain the mean Z-score but height is already at about −3 at 2 years and fluctuates around this value along the follow-up; as to weight, difference in height seems to increase from 15 years in boys. Results in Fig. 3 clearly show that primarily difference in dimensions is established early in life, certainly during infancy (Fig. 3a,b).


Growth pattern from birth to adulthood in African pygmies of known age.

Rozzi FV, Koudou Y, Froment A, Le Bouc Y, Botton J - Nat Commun (2015)

Spaghetti plots of individual Sempe32-based Z-scores of height and weight over time.Each colour line represents one subject. The plain black line represents the average trend in the population, thanks to a LOESS-based approach. The flexibility of the LOESS regression function was control through the smoothing parameter ‘span' set at 0.3 for weight and 0.8 for height. (a,b) Z-score of weight at birth in boys and girls from the Baka population is close to zero, which means that weight at birth is not very different from the Sempe reference one. Then, the mean Z-score decreases rapidly until 2 or 3 years and remained around −2 until the end of follow-up in girls and until 15 in boys where mean Z-score seems to decrease again. (c,d) Mean Z-score of height (available from 2 years), is already at about −3 at this age and fluctuates around this value along the follow-up. In boys, as for weight, height difference seems to increase a little from 15 years.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525207&req=5

f3: Spaghetti plots of individual Sempe32-based Z-scores of height and weight over time.Each colour line represents one subject. The plain black line represents the average trend in the population, thanks to a LOESS-based approach. The flexibility of the LOESS regression function was control through the smoothing parameter ‘span' set at 0.3 for weight and 0.8 for height. (a,b) Z-score of weight at birth in boys and girls from the Baka population is close to zero, which means that weight at birth is not very different from the Sempe reference one. Then, the mean Z-score decreases rapidly until 2 or 3 years and remained around −2 until the end of follow-up in girls and until 15 in boys where mean Z-score seems to decrease again. (c,d) Mean Z-score of height (available from 2 years), is already at about −3 at this age and fluctuates around this value along the follow-up. In boys, as for weight, height difference seems to increase a little from 15 years.
Mentions: The plot of individual Sempe32-based Z-scores of height and weight over time (Fig. 3) shows that Baka birth with a weight close to standard values and decrease markedly during the first month of life becoming around −2 Z-scores from 2 to 3 years until adulthood in girls; in boys, difference seems to increases from 15 years of age. Data on height in Baka for earliest years of post-natal life are scarce and does not allow to obtain the mean Z-score but height is already at about −3 at 2 years and fluctuates around this value along the follow-up; as to weight, difference in height seems to increase from 15 years in boys. Results in Fig. 3 clearly show that primarily difference in dimensions is established early in life, certainly during infancy (Fig. 3a,b).

Bottom Line: Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life.It then more or less follows the standard pattern, with a growth spurt at adolescence.Their life history variables do not allow the Baka to be distinguished from other populations.

View Article: PubMed Central - PubMed

Affiliation: UPR 2147 CNRS, 44 rue de l'Amiral Mouchez, 75014 Paris, France.

ABSTRACT
The African pygmy phenotype stems from genetic foundations and is considered to be the product of a disturbance in the growth hormone-insulin-like growth factor (GH-IGF) axis. However, when and how the pygmy phenotype is acquired during growth remains unknown. Here we describe growth patterns in Baka pygmies based on two longitudinal studies of individuals of known age, from the time of birth to the age of 25 years. Body size at birth among the Baka is within standard limits, but their growth rate slows significantly during the first two years of life. It then more or less follows the standard pattern, with a growth spurt at adolescence. Their life history variables do not allow the Baka to be distinguished from other populations. Therefore, the pygmy phenotype in the Baka is the result of a change in growth that occurs during infancy, which differentiates them from East African pygmies revealing convergent evolution.

No MeSH data available.


Related in: MedlinePlus