Young-Geier Autism Study: What the—? (Part 3)

This post represents the third installment of my review of the study by Young et al, which links exposure to Thimerosal-containing vaccines with autism. Previous posts on the subject can be found here, here, here, and here.

Results

Table 3 presents the rate ratios and 95% confidence intervals for each diagnosis assuming a µg increase in mercury exposure from Thimerosal-containing vaccines administered from birth to 7 months and birth to 13 months. It was observed that there were significantly increased rate ratios for the neurodevelopmental disorders of autism, autism spectrum disorder (ASD), hyperkinetic syndrome of childhood (attention deficity disorder/attention deficity hyperactivity disorder), developmental disorder/learning disorder—not otherwise specificied, disturbance of emotions specific to childhood and adolescence, and tics following additional Hg exposure from Thimerosal-containing childhood vaccines...By contrast, no significantly increased rate ratios for the control disorders of pneumonia, congenital anomalies, and failure to thrive were observed with increasing Hg exposure from Thimerosal containing vaccines.

The rate ratios, given a 100-µg increase in vaccine-related ethylmercury exposure, are reproduced below from Young et al's Table 3:

Condition	Rate Ratio (95% CI), Birth-7 Months	Rate Ratio (95% CI),  Birth-13 Months
Neurodevelopmental
Autism	2.87 (1.19, 6.94)	2.62 (1.15, 6.01)
Autism spectrum	2.44 (1.16, 5.10)	2.20 (1.10, 4.40)
Hyperkinetic syndrome	3.15 (2.38, 4.17)	4.51 (3.48, 5.84)
Developmental disorder/ learning disorder—not otherwise specified	1.73 (1.08, 2.75)	1.81 (1.17, 2.80)
Disturbance of emotions	2.27 (1.36, 3.80)	2.91 (1.81, 4.68)
Tics	3.39 (1.64, 6.79)	4.11 (2.12, 7.94)
Control
Pneumonia	0.98 (0.86, 1.11)	0.92 (0.82, 1.04)
Congenital anomalies	0.62 (0.34, 1.14)	0.57 (0.33, 1.00)
Failure to thrive (FTT)	1.05 (0.74, 1.47)	0.92 (0.67, 1.27)

There's little to say about these numbers, other than they have to be taken on faith, which is a dubious proposition in my opinion. The rate (or risk) ratios for the neurodevelopmental disorders are very high, suggesting (in some cases) a several-hundred-fold increased risk for a neurodevelopmental disorder with what is really a very small (ie, 100-µg) increase in ethylmercury exposure. The 95% confidence intervals for the neurodevelopmental disorders are also exceptionally wide, especially when compared with those for the control conditions. The following graphs of the rate ratios and 95% CIs illustrate this point.

Birth-7 Months

Birth-13 Months

Also, given these data, couldn't it be concluded (although a P value is not provided) that a 100-ug increase in vaccine-related ethylmercury exposure reduces the risk of congenital anomalies by approximately 40%?

Next: Discussion.