Response to Which Period of Growth Is Determinant for Blood Pressure?
We thank Chiolero et al1 for their comments2 and for drawing our attention to their interesting article.3 They raise an important point about the relative influence of different growth periods on blood pressure (BP). They suggest that our data support the view that growth between infancy and age 10 years is more important than later growth. We do not take this view, because we did not examine growth after age 10 years. Our interpretation is that BP increases with the acquisition of mass, in any form, at any time after birth. This effect appears strongest in children who were small at birth. Periods during which greatest absolute mass acquisition occurred were most strongly associated with BP. Childhood BP tracks into adulthood, and we postulate that our findings might, therefore, be important for understanding adult BP. However, their importance relative to later periods of growth is not yet established.
The 3 cohorts studied by Chiolero et al3 were smaller and differed in their racial and geographical characteristics from the Avon Longitudinal Study of Parents and Children. The impact of this is unknown. Therefore, comparisons of the studies should be interpreted cautiously. However, they found that growth to 15.5 years was also associated with BP, showing that the effect of growth on BP continues. The pattern of associations in their study led to their suggestion that, whenever BP is examined, recent growth will always be a stronger determinant than earlier growth. However, there may be some caveats, as described below.
First, in their figure,1 95% CIs for most of their estimates overlap substantially, suggesting little statistical difference between these periods. This limits the ability to draw robust conclusions from the pattern of the data.
Second, weight gain velocity increases steadily after 2 years, rising sharply during puberty. Therefore, both studies are of growth periods where growth acceleration is occurring. If each sequential period accounts for more absolute mass acquisition than the last, the effect on BP might be greater, consistent with our hypothesis that overall mass acquisition influences BP. Therefore, studies are needed with measures of growth after puberty, when growth velocity declines.
We thank Chiolero et al1 for pointing out that growth in childhood after age 10 years may also be important in the determination of BP. They make an interesting suggestion about the relative importance of different growth periods, which highlights the need for long-term studies into adulthood. These may soon be available now that Avon Longitudinal Study of Parents and Children participants are 21 years old.
John E. Deanfield
Institute of Cardiovascular Science
University College London
London, United Kingdom
Sources of Funding
This work was supported by a National Institute for Health Research Biomedical Research Centre grant (AJ [09CC04]) and a British Heart Foundation grant (JED [FS/05/125]).
Letters to the Editor will be published, if suitable, as space permits. They should not exceed 1000 words (typed double-spaced) in length and may be subject to editing or abridgment.
- © 2012 American Heart Association, Inc.
- Chiolero A,
- Paradis G,
- Bovet P
- Jones A,
- Charakida M,
- Falaschetti E,
- Hingorani AD,
- Finer N,
- Masi S,
- Donald AE,
- Lawlor DA,
- Davey Smith G,
- Deanfield JE