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Early-life nutritional and environmental determinants of thymic size in infants born in rural Bangladesh.

Moore SE, Prentice AM, Wagatsuma Y, Fulford AJ, Collinson AC, Raqib R, Vahter M, Persson LA, Arifeen SE - Acta Paediatr. (2009)

Bottom Line: At all ages, TI was positively associated with infant weight and strongly associated with the month of measurement.Longer duration of exclusive breastfeeding resulted in a larger TI at 52 weeks.TI at birth and at 8 weeks correlated positively with birth weight, but by 24 and 52 weeks and when adjusted for infant weight this effect was no longer present.

View Article: PubMed Central - PubMed

Affiliation: MRC Keneba, MRC Laboratories, Banju, The Gambia. Sophie.Moore@lshtm.ac.uk

ABSTRACT

Aim: The aim was to assess the impact of nutritional status and environmental exposures on infant thymic development in the rural Matlab region of Bangladesh.

Methods: In a cohort of N(max) 2094 infants born during a randomized study of combined interventions to improve maternal and infant health, thymic volume (thymic index, TI) was assessed by ultrasonography at birth and at 8, 24 and 52 weeks of age. Data on birth weight, infant anthropometry and feeding status were also collected.

Results: At all ages, TI was positively associated with infant weight and strongly associated with the month of measurement. Longer duration of exclusive breastfeeding resulted in a larger TI at 52 weeks. TI at birth and at 8 weeks correlated positively with birth weight, but by 24 and 52 weeks and when adjusted for infant weight this effect was no longer present. Thymic size was not affected by pre-natal maternal supplementation or by socioeconomic status but was correlated to arsenic exposure during pregnancy.

Conclusion: In this population of rural Bangladeshi infants, thymic development is influenced by both nutritional and environmental exposures early in life. The long-term functional implications of these findings warrant further investigation.

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Related in: MedlinePlus

Relative size of thymus variation with time of year plotted at birth and at 8, 24 and 52 weeks of age. The curves are the seasonal component of equation (1) fitted by multiple regression. They show the mean TI difference from the overall average at different times of the year. Post-natally, the thymus is largest in the first half of the year and smallest in the second half of the year. The picture is rather different at birth where there appeared to be two peaks: at the turn of the year and at mid-year. The difference between the patterns at the different post-natal ages is not significant but these do differ significantly from the pattern at birth.
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fig02: Relative size of thymus variation with time of year plotted at birth and at 8, 24 and 52 weeks of age. The curves are the seasonal component of equation (1) fitted by multiple regression. They show the mean TI difference from the overall average at different times of the year. Post-natally, the thymus is largest in the first half of the year and smallest in the second half of the year. The picture is rather different at birth where there appeared to be two peaks: at the turn of the year and at mid-year. The difference between the patterns at the different post-natal ages is not significant but these do differ significantly from the pattern at birth.

Mentions: The effect of month of measurement on mean TI at each time point and for all time points pooled is illustrated in Figure 2. Adjusted for sex and infant length at the time of measurement, a significant association with season of measurement was observed at all time points, with the exception of the measurements made at 8 weeks of age: Birth p = 0.0012; 8-week p = 0.0739; 24-week p ≤ 0.0001 and 52-week p = 0.0002. There are three broad seasons in Bangladesh: the hot and dry season (March to June), the monsoon season (July to September) and winter (October to February). At birth, mean TI showed a bimodal pattern, with largest TIs observed when measured in June and December and smallest in March and September. For the measurements made when the infants were 8, 24 and 52 weeks old, TIs peaked only once during the hot and dry months of the year falling in size during the monsoon and winter months. When the measurements at all time points were pooled, the seasonal pattern differed significantly between time points (likelihood ratio test χ2 on 6 df = 21.18; p = 0.0017). This difference was almost entirely due to the difference between the pattern at birth and the patterns observed post-natally (likelihood ratio test χ2 on 2 df = 12.51; p = 0.0019) while no further difference was detected between the post-natal patterns (likelihood ratio test χ2 on 4 df = 8.67; p = 0.070). The seasonal pattern with the time points pooled is also illustrated in Figure 2.


Early-life nutritional and environmental determinants of thymic size in infants born in rural Bangladesh.

Moore SE, Prentice AM, Wagatsuma Y, Fulford AJ, Collinson AC, Raqib R, Vahter M, Persson LA, Arifeen SE - Acta Paediatr. (2009)

Relative size of thymus variation with time of year plotted at birth and at 8, 24 and 52 weeks of age. The curves are the seasonal component of equation (1) fitted by multiple regression. They show the mean TI difference from the overall average at different times of the year. Post-natally, the thymus is largest in the first half of the year and smallest in the second half of the year. The picture is rather different at birth where there appeared to be two peaks: at the turn of the year and at mid-year. The difference between the patterns at the different post-natal ages is not significant but these do differ significantly from the pattern at birth.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2721967&req=5

fig02: Relative size of thymus variation with time of year plotted at birth and at 8, 24 and 52 weeks of age. The curves are the seasonal component of equation (1) fitted by multiple regression. They show the mean TI difference from the overall average at different times of the year. Post-natally, the thymus is largest in the first half of the year and smallest in the second half of the year. The picture is rather different at birth where there appeared to be two peaks: at the turn of the year and at mid-year. The difference between the patterns at the different post-natal ages is not significant but these do differ significantly from the pattern at birth.
Mentions: The effect of month of measurement on mean TI at each time point and for all time points pooled is illustrated in Figure 2. Adjusted for sex and infant length at the time of measurement, a significant association with season of measurement was observed at all time points, with the exception of the measurements made at 8 weeks of age: Birth p = 0.0012; 8-week p = 0.0739; 24-week p ≤ 0.0001 and 52-week p = 0.0002. There are three broad seasons in Bangladesh: the hot and dry season (March to June), the monsoon season (July to September) and winter (October to February). At birth, mean TI showed a bimodal pattern, with largest TIs observed when measured in June and December and smallest in March and September. For the measurements made when the infants were 8, 24 and 52 weeks old, TIs peaked only once during the hot and dry months of the year falling in size during the monsoon and winter months. When the measurements at all time points were pooled, the seasonal pattern differed significantly between time points (likelihood ratio test χ2 on 6 df = 21.18; p = 0.0017). This difference was almost entirely due to the difference between the pattern at birth and the patterns observed post-natally (likelihood ratio test χ2 on 2 df = 12.51; p = 0.0019) while no further difference was detected between the post-natal patterns (likelihood ratio test χ2 on 4 df = 8.67; p = 0.070). The seasonal pattern with the time points pooled is also illustrated in Figure 2.

Bottom Line: At all ages, TI was positively associated with infant weight and strongly associated with the month of measurement.Longer duration of exclusive breastfeeding resulted in a larger TI at 52 weeks.TI at birth and at 8 weeks correlated positively with birth weight, but by 24 and 52 weeks and when adjusted for infant weight this effect was no longer present.

View Article: PubMed Central - PubMed

Affiliation: MRC Keneba, MRC Laboratories, Banju, The Gambia. Sophie.Moore@lshtm.ac.uk

ABSTRACT

Aim: The aim was to assess the impact of nutritional status and environmental exposures on infant thymic development in the rural Matlab region of Bangladesh.

Methods: In a cohort of N(max) 2094 infants born during a randomized study of combined interventions to improve maternal and infant health, thymic volume (thymic index, TI) was assessed by ultrasonography at birth and at 8, 24 and 52 weeks of age. Data on birth weight, infant anthropometry and feeding status were also collected.

Results: At all ages, TI was positively associated with infant weight and strongly associated with the month of measurement. Longer duration of exclusive breastfeeding resulted in a larger TI at 52 weeks. TI at birth and at 8 weeks correlated positively with birth weight, but by 24 and 52 weeks and when adjusted for infant weight this effect was no longer present. Thymic size was not affected by pre-natal maternal supplementation or by socioeconomic status but was correlated to arsenic exposure during pregnancy.

Conclusion: In this population of rural Bangladeshi infants, thymic development is influenced by both nutritional and environmental exposures early in life. The long-term functional implications of these findings warrant further investigation.

Show MeSH
Related in: MedlinePlus