Friday, January 19, 2007

Clarification

'Of course, a positive correlation by itself is not enough to deduce a causal relationship, but certainly one would be very foolish to conclude from the evidence that "the link between maltreatment and heart disease is NOT CAUSED by growing up in poorer families..."

This is a comment from Rose in response to a post yesterday. She admits not reading the newspaper report and then questions whether I have. Rose, I wouldn't write a post without checking my facts.

Are you saying the researchers are "very foolish"? Quote;

The study also showed that the link between maltreatment and inflammation was not caused by growing up in poorer families or with a less healthy lifestyle.

Do you know what that means? They controlled for those factors. They must have found the link existed even where families were more affluent and had healthier lifestyles.To me that is the most interesting aspect of this particular paper.

And it is notable that the Public Health Association chose to ignore this aspect and instead talk about child maltreatment and smacking (as if they are one and the same thing) in order to further promote Sue Bradford's bill.

Just for good measure here is what the actual paper says (with my emphasis).

Abstract;
Stress in early life has been associated with insufficient glucocorticoid signaling in adulthood, possibly affecting inflammation processes. Childhood maltreatment has been linked to increased risk of adult disease with potential inflammatory origin. However, the impact of early life stress on adult inflammation is not known in humans. We tested the life-course association between childhood maltreatment and adult inflammation in a birth cohort followed to age 32 years as part of the Dunedin Multidisciplinary Health and Development Study. Regression models were used to estimate the effect of maltreatment on inflammation, adjusting for co-occurring risk factors and potential mediating variables. Maltreated children showed a significant and graded increase in the risk for clinically relevant C-reactive protein levels 20 years later, in adulthood [risk ratio (RR) = 1.80, 95% confidence interval (CI) = 1.26-2.58]. The effect of childhood maltreatment on adult inflammation was independent of the influence of co-occurring early life risks (RR = 1.58, 95% CI = 1.08-2.31), stress in adulthood (RR = 1.64, 95% CI = 1.12-2.39), and adult health and health behavior (RR = 1.76, 95% CI = 1.23-2.51). More than 10% of cases of low-grade inflammation in the population, as indexed by high C-reactive protein, may be attributable to childhood maltreatment. The association between maltreatment and adult inflammation also generalizes to fibrinogen and white blood cell count. Childhood maltreatment is a previously undescribed, independent, and preventable risk factor for inflammation in adulthood. Inflammation may be an important developmental mediator linking adverse experiences in early life to poor adult health.

2 comments:

Anonymous said...

Thanks Lindsay.
Yes, that is interesting and indeed surprising. And, yes I understand what regression analysis is perfectly well. I stated that I had not read that paper (we all have time-restraints), and in your original post you did not state that the researchers controlled for other risk-factors (i.e. poverty). Thus I questioned what appeared to be your own conclusion (but was really part of the paper).
Of course, I am happy to change my view in the light of further information.

Anonymous said...

I can't say I'm convinced. I thought inflammatory reaction - as indicated by high white blood corpuscle & neutraphil count - to be an artefact of bodies reaction to invasive stuff, be it disease or something ingested/breathed in.
They may have the figures, but it seems more logical that immediate stimuli affect inflammatory response rather than historical ones.
I feel they are missing something ... seems a spurious relationship.