Twin Data that Made a Big Difference, and that Deserve to be Better-Known and Used in Teaching

Figures & data

Table 1. Replication of the table “Factors for mother-to-infant transmission of HIV-1 infection in 115 prospectively identified twin sets” as published in Duliège et al. (1995), created using the hivtwins dataset.

		No. of sets by HIV-1 infection status				% HIV-1 infected
	Total no. of sets	Neither infected	Both infected	A twin infected	B twin infected	% Overall	% A twins	% B twins
All sets	115	81	11	19	4	20	26	13
Delivery
- Both vaginal	65	41	9	14	1	25	35	15
- Both cesarean	38	30	1	5	2	12	16	8
Zygosity
- Monozygotic	24	17	3	4	0	21	29	12
- Dizygotic	73	49	7	13	4	21	27	15
Birth weight concordance
- Twin A heavier	22	17	3	1	1	18	18	18
- Same (+/-10%)	53	37	5	11	0	20	30	9
- Twin A lighter	28	17	2	6	3	23	29	18
Gestational age (wk)
- <34	27	20	3	3	1	19	22	15
- 34–37	55	39	3	11	2	17	25	9
- >37	23	13	5	5	0	33	43	22
Mother's race
- Black	72	51	9	9	3	21	25	17
- White	22	14	2	6	0	23	36	9
- Other/unknown	21	16	0	4	1	12	19	5
Mother's route of infection
- Intravenous drug abuse	57	45	4	6	2	14	18	11
- Sexual/other	53	36	4	11	2	20	28	11
Mother with AIDS
- Yes	11	6	1	3	1	27	36	18
- No	54	42	4	7	1	15	20	9
Continent
- North America	72	54	8	8	2	18	22	14
- Europe	26	19	1	5	1	15	23	8
- Africa	16	8	2	5	1	31	44	19
Breast fed
- Both	12	8	0	3	1	17	25	8
- Neither	63	45	7	10	1	20	27	13

Figure 1. “Compass plot” shows rates of HIV-1 infection for first born and second born twins given method of delivery; based on data of Duliège et al. (1995).

Table 2. The two-by-two table summarizes HIV status for the 115 pairs of twins.

		Second twin
		Not infected	Infected
First twin	Not infected	81	4	85
	Infected	19	11	30
		100	15	115

Duliège, A. M., Amos, C. I., Felton, S., Biggar, R. J., and Goedert, J. J. (1995), “Birth Order, Delivery Route, and Concordance in the Transmission of Human Immunodeficiency Virus Type 1 from Mothers to Twins,” The Journal of Pediatrics, 126(4), 625–632.

 PubMed Web of Science ®Google Scholar