Education, cognitive ability, and cause-specific mortality: A structural approach

Figures & data

Figure 1 Graphical representation of the structural model on education, cognitive ability, and cause-specific mortality

Notes: Latent cognitive ability, θ, influences the individual education attained, E, and the (potential) cause-specific hazard, ${\lambda }_c^{\left(e\right)}$, for each cause, c, and each education level, E = e. Educational attainment and the cause-specific hazard also depend on observed covariates X_E or X_c. The IQ measurement, IQ, depends on the latent cognitive ability and on observed covariates X_IQ. Note that X_E, X_c, and X_IQ may overlap or even be the same.

Table 1 Sample characteristics, Swedish conscripts born 1951–60 (N = 446,545)

	Level of education (row percentages)
	Compulsory	Some secondary (two years)	Full secondary (three years)	Post-secondary
Mother’s socio-economic status
Not classified	26	42	10	22
Unskilled workers	26	41	12	21
Skilled workers	26	42	11	20
Farmers	29	37	12	23
Non-manual (low)	12	27	15	46
Non-manual (intermediate)	9	21	14	56
Non-manual (high)	9	17	16	59
Father’s education
Less than 9 years	28	41	11	20
9–10 years	17	33	15	35
Some secondary (maximum 12 years total)	16	36	14	33
Full secondary (maximum 13 years total)	11	28	14	47
Post-secondary	6	16	13	64
Missing	26	36	12	26
Birth measures
Mother <20 at birth	28	42	11	18
Birth order 1	19	34	13	34
Birth order 2	21	36	13	31
Birth order 3	25	37	11	26
Birth order 4	28	40	11	21
Birth order >4	34	41	9	16
IQ measure, age 18^a
Average IQ	4.0	4.6	5.7	6.5
Mortality (ages 18–63)
Number of deaths	8,770	9,451	2,506	3,829
Deaths per 1,000	90.8	59.1	45.3	28.4
Causes of death per 1,000 men
Neoplasms	18.2	14.0	13.1	10.0
Cardiovascular diseases	18.4	13.9	10.4	6.3
External causes	31.5	16.5	11.7	6.8
‘Other’ causes	22.6	14.7	10.1	5.3
N	96,598	160,000	55,313	134,634

^aIQ scores run from low (1) to high (9).

Source: Swedish Military Service Conscription Register linked to Swedish administrative registers.

Figure 2 Cumulative incidence curves by level of education for (a) neoplasms, (b) cardiovascular diseases, (c) external causes, and (d) ‘other’/unknown causes; Swedish conscripts born 1951–60

Source: Authors’ calculations based on Swedish Military Service Conscription Register linked to Swedish administrative registers.

Table 2 Cox proportional hazards odds ratios of education on cause-specific mortality, Swedish conscripts born 1951–60, ages 18–63

	Educational gain^a
	(2)	(3)	(4)
	Neoplasms
Unadjusted	0.79**	0.87**	0.79**
Controls^b	0.78**	0.88**	0.79**
Controls^b and IQ	0.79**	0.90**	0.78**
	Cardiovascular diseases
Unadjusted	0.77**	0.71**	0.62**
Controls^b	0.76**	0.72**	0.60**
Controls^b and IQ	0.82**	0.78**	0.62**
	External causes
Unadjusted	0.52**	0.69**	0.59**
Controls^b	0.51**	0.69**	0.60**
Controls^b and IQ	0.52**	0.74**	0.62**
	‘Other’ causes
Unadjusted	0.66**	0.65**	0.54**
Controls^b	0.64**	0.64**	0.54**
Controls^b and IQ	0.69**	0.70**	0.56**

^a(2) Some secondary education (two years); (3) full secondary education (three years); (4) post-secondary (university degree or PhD). Odds ratios show educational gain in mortality for this education level compared with the level below.

^bControls include maternal socio-economic status around birth, paternal education, year of birth, and birth order.

**p < 0.01.

Source: Authors’ calculations based on Swedish Military Service Conscription Register linked to Swedish administrative registers.

Table 3 Months lost and educational gain (at ages 18–63) by cause of death and level of education, structural model, Swedish conscripts born 1951–60

	Level of education^a
	(1)	(2)	(3)	(4)
	Months lost
Neoplasm	3.45	2.32	2.19	1.69
Cardiovascular diseases	2.48	2.18	1.76	1.15
External causes	11.26	4.52	3.59	2.58
‘Other’ causes of death	3.45	2.44	1.82	1.15
Total	20.63	11.45	9.37	6.57
	Educational gain (months)
Neoplasm		1.13**	0.13	0.50*
Cardiovascular diseases		0.30	0.42	0.61*
External causes		6.74**	0.93**	1.01**
‘Other’ causes of death		1.01**	0.62**	0.67**
Total		9.18**	2.09**	2.80**

^a(1) Compulsory (less than ten years in total); (2) some secondary education (two years); (3) full secondary education (three years); (4) post-secondary (university degree or PhD). Educational gain shows improvement in mortality for this education level compared with the level below.

*p < 0.05; **p < 0.01.

Source: As for Figure 2.

Figure 3 (a) Months lost and (b) educational gains (at ages 18–63): differences between Cox model and structural model, Swedish conscripts born 1951–60

Notes: (a) The difference in months lost by education level for the Cox model compared with the structural model, where a positive value indicates that the Cox model overestimates the months lost. (b) The difference between the Cox model and the structural model in the implied educational gains in reducing the number of months lost by improving the education level, where a positive value indicates that the Cox model overestimates this educational gain. See Table 3 for the results from the structural model.Source: As for Figure 2.