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. Author manuscript; available in PMC: 2019 Jul 1.
Published in final edited form as: J Autism Dev Disord. 2018 Jul;48(7):2379–2395. doi: 10.1007/s10803-018-3495-z

Table 5.

Mean digit ratio females, examination of ASD subtypes, study to explore early development

Digit ratio × 100
ASD with given
condition or
characteristic		 Digit ratio × 100
ASD without
given condition
or characteristic		 Digit ratio × 100
POP		 Digit ratio difference
ASD with
condition minus
POP		 p Value
ASD with
condition vs
POP		 Digit ratio difference
ASD without
condition minus
POP		 p Value
ASD without
condition versus
POP
Left hand
  Intellectual disability
    Total, unadjusted, n = 487 94.68 95.42 94.61 0.07 0.874 0.81 0.193
    Total, adjusteda, n = 458 94.27 94.79 93.70 0.57 0.224 1.09 0.085
    Complete restricted, adjusteda,b, n = 258 95.16 95.49 93.54 1.62 0.036 1.95 0.035
  Diagnosis of birth defect, Down syndrome, fragile X syndrome, Rett syndrome, or tuberous sclerosis
    Total, unadjusteda, n = 481 96.73 94.52 94.62 2.10 0.020 − 0.10 0.809
    Total, adjusted, n = 460 96.00 94.16 93.69 2.31 0.009 0.47 0.265
    Complete restricted, adjusteda,b, n = 259 –c 94.99 93.46 – – 1.53 0.018
  Dysmorphic
    Total, unadjusted, n = 244 94.92 95.14 94.36 0.56 0.497 0.77 0.131
    Total, adjusteda, n = 232 95.02 95.05 94.43 0.59 0.488 0.63 0.213
    Complete restricted, adjusteda,b, n = 114 –c 95.82 94.21 – – 1.61 0.044
Right hand
  Intellectual disability
    Total, unadjusted, n = 487 94.79 95.44 94.87 − 0.08 0.859 0.57 0.369
    Total, adjusteda, n = 459 94.40 94.65 93.90 0.50 0.304 0.75 0.258
    Complete restricted, adjusteda,b, n = 259 93.63 94.51 93.88 − 0.25 0.747 0.63 0.492
  Diagnosis of birth defect, Down syndrome, fragile X syndrome, Rett syndrome, or tuberous sclerosis
    Total, unadjusted, n = 482 96.91 94.64 94.89 2.02 0.020 − 0.25 0.552
    Total, adjusteda, n = 461 96.23 94.23 93.97 2.26 0.013 0.26 0.555
    Complete restricted, adjusteda,b, n = 260 –c 93.72 93.83 – – − 0.10 0.872
  Dysmorphic
    Total, unadjusted, n = 246 94.39 95.38 94.62 − 0.23 0.796 0.76 0.173
    Total, adjusteda, n = 234 93.98 94.53 94.02 − 0.04 0.968 0.51 0.365
    Complete restricted, adjusteda,b, n = 115 –c 94.40 93.84 – – 0.56 0.516

Statistically significant findings are indicated in bold

Total sample sizes for each analysis type indicated in table. Samples sizes for individual study groups varied as follows:

N = 26–77 for ASD with intellectual disability

N = 17–34 for ASD without intellectual disability

N = 4–17 for ASD with a birth defect/genetic disorder

N = 40–93 for ASD without a birth defect/genetic disorder

N = 5–19 for dysmorphic ASD

N = 30–67 for non-dysmorphic ASD

N = 79–377 for the POP group

ASD autism spectrum disorder case group, POP population control group

a

Adjusted models included child race-ethnicity, child age at scan, birth order, maternal age at birth, maternal education at birth and maternal prepregnancy body mass index

b

Complete restricted sample was restricted to children born in singleton term births with no pre-pregnancy maternal infertility disorders, no use of maternal ovulation medications or progesterone, and no maternal smoking during pregnancy

c

Data not shown if estimates were of questionable reliability due to sparse data