Parental Separation and Semen Quality in Young Men: A Population-Based Cohort Study

Figures & data

Figure 1 Flowchart on the inclusion of participants in the fetal programming of semen quality (FEPOS) cohort, nested within the Danish National Birth Cohort, Denmark, 1998–2019.

Table 1 Baseline Characteristics. Maternal and Semen Quality Characteristics According to Parental Separation in Pregnancy Among 1058 Young Men from FEPOS, Denmark, 1998–2019

	Parental Separation				Missing Values
	Yes		No
	No.	%	No.	%	No.	%
	22	2.1	1,036	97.9
Maternal characteristics
Maternal age at delivery; mean years (SD)	31.5 (4.8)		30.5 (4.1)		<5^a	0.5
Maternal social class; n(%)					0	0.0
High-/low-grade professional	5	22.7	704	68.0
Skilled/unskilled worker	8	36.4	292	28.2
Student/economically inactive	9	40.9	40	3.8
Smoking 1. trimester; n(%)					0	0.0
0 cigarettes/day	7	31.8	808	78.0
1–10 cigarettes/day	>10	>45.5	194	18.7
>10 cigarettes/day	<5^a	<22.7	34	3.28
Unplanned pregnancy; n(%)					6	0.6
No	6	27.3	871	84.1
Yes	16	72.7	159	15.4
Precision variables
Abstinence time; mean days (SD)	2.1 (0.9)		2.3 (1.5)		5	0.5
0–2 days; n(%)	7	31.8	359	34.7
>2 days; n(%)	15	68.2	672	64.9
Place of semen sample collection; n(%)					10	1.0
At home	<5^a	<22.7	134	12.9
In the clinic	>17	>77.3	892	86.1
Spillage; n(%)					9	0.9
Yes	<5^a	<22.7	181	17.5
No	>17	>77.3	846	81.7
Interval ejaculation - analysis; mean min (SD)	53.0 (17.5)		49.9 (19.5)		12	1.2
0–60 min; n(%)	13	59.1	773	74.6
>60 min; n(%)	9	40.9	251	24.2

Notes: ^aDue to local data regulations, it is not allowed to report numbers smaller than five, why the numbers in the table have been changed to mask the numbers smaller than five.

Abbreviations: SD, standard deviation.

Table 2 Baseline Characteristics. Maternal and Semen Quality Characteristics According to Parental Separation in Childhood Among 696 Young Men from FEPOS, Denmark, 1998–2019

	Parental Separation				Missing Values
	Yes		No
	No.	%	No.	%	No.	%
	160	23.0	536	77.0
Maternal characteristics
Maternal age at delivery; mean years (SD)	30 (4.4)		30.5 (4.0)		<5^a	0.7
Maternal social class; n(%)					0	0.0
High-/low-grade professional	94	60.2	371	69.2
Skilled/unskilled worker	55	33.1	139	25.9
Student/economically inactive	11	6.6	26	4.9
Smoking 1. trimester; n(%)					0	0.0
0 cigarettes/day	108	66.9	442	82.5
1–10 cigarettes/day	44	27.7	81	15.1
> 10 cigarettes/day	8	5.4	13	2.4
Unplanned pregnancy; n(%)					<5^a	0.7
No	119	74.4	<470	<87.7
Yes	41	25.6	<66	<12.3
Precision variables
Abstinence time; mean days (SD)	2.2 (1.2)		2.4 (1.6)		<5^a	0.7
0–2 days; n(%)	59	36.9	186	34.7
>2 days; n(%)	<101	<63.1	<350	<65.3
Place of semen sample collection; n(%)					8	1.2
At home	<28	<17.5	<68	<12.7
In the clinic	132	82.5	468	87.3
Spillage; n(%)					8	1.2
Yes	<26	<16.3	<108	<20.1
No	134	83.8	428	79.9
Interval ejaculation - analysis; mean min (SD)	51.3 (20.7)		50.0 (19.4)		6	0.9
0–60 min; n(%)	109	68.1	407	75.9
>60 min; n(%)	<51	31.9	<129	<24.1

Notes: ^aDue to local data regulations, it is not allowed to report numbers smaller than five, why the numbers in the table have been changed to mask the numbers smaller than five.

Abbreviations: SD, standard deviation.

Table 3 Descriptive Statistics^a. Semen Quality Characteristics and Testes Volume According to (A) Parental Separation in Pregnancy; (B) Parental Separation in Childhood; and (C) Parental Separation According to Timing of Parental Separation in Childhood in Young Men from FEPOS, Denmark, 2017–2019

A.

Parental Separation in Pregnancy (n = 1058)

Missing Values

Yes

No

No.

%

No.

%

No.

%

22

2.1

1,036

97.9

Volume (mL)^b

2.9 (1.5–4.8)

2.7 (1.3–4.7)

192

18

Concentration (mill/mL)

34 (6–98)

39 (8–113)

6

0.6

Total sperm count (mill)^b

96 (20–336)

102 (18–338)

192

18

Progressive motility (PR %)^c

65 (47–77)

63 (41–80)

23

2.2

Morphology (% normal)^c

8.4 (1.0–13.4)

6.0 (1.0–13.0)

29

2.7

Average testicular volume (mL)

19 (8–24)

15 (9–24)

<5^d

0.5

B.

Parental Separation in Childhood (n = 696)

Yes

No

Missing Values

No.

%

No.

%

No.

%

160

23

536

77

Volume (mL)^b

2.5 (1.4–4.5)

2.7 (1.3–4.9)

134

19

Concentration (mill/mL)

37 (5–90)

39 (8–112)

<5^d

0.7

Total sperm count (mill)^b

96 (12–324)

102 (18–349)

134

19

Progressive motility (a %)^c

64 (39–81)

62 (38–79)

14

2.0

Morphology (% normal)^c

6.0 (1.0–13.0)

6.0 (1.0–13.0)

18

2.6

Average testicular volume (mL)

15 (9–24)

15 (9–25)

<5^d

0.5

C.

Parental Separation in Childhood (n = 696)

Yes

Yes

Yes

No

Missing Values

From Birth

In Early Childhood

In Late Childhood

No.

%

No.

%

No.

%

No.

%

No.

%

10

1.4

83

11.9

67

9.6

536

77

Volume (mL)^b

3.8 (2.5–4.7)

2.4 (1.3–4.2)

2.6 (1.4–4.6)

2.7 (1.3–4.9)

134

19

Concentration (mill/mL)

40 (26–79)

37 (7–88)

36 (3–110)

39 (8–112)

<5^d

0.7

Total sperm count (mill)^b

158 (66–300)

92 (13–292)

96 (10–324)

102 (18–349)

134

19

Progressive motility (a %)^c

62 (53–68)

64 (37–80)

65 (41–84)

62 (38–79)

14

2.0

Morphology (% normal)^c

11.0 (7.2–13.4)

6.0 (1.0–12.5)

5.5 (1.0–13.0)

6.0 (1.0–13.0)

18

2.6

Average testicular volume (mL)

19 (14–23)

14 (8–20)

16 (10–25)

15 (9–25)

<5^d

0.5

Notes: ^aReported as 50th percentile (10th–90th). All percentiles are pseudo percentiles calculated from the average of five values. ^bExcluding samples from participants reporting spillage. ^cExcluding samples with azoospermia. ^dDue to local data regulations, it is not allowed to report numbers smaller than five.

Abbreviations: p10, 10th pseudo percentile; p50, 50th pseudo percentile; p90, 90th pseudo percentile.

Figure 2 Main results for parental separation in pregnancy or in childhood. Relative percentage differences in semen quality and testes volume according to parental separation in pregnancy (square and dark grey (N=1,058)) or in childhood (circle and black (N=696)). Parental separation relatively to no parental separation (vertical line). Adjusted for maternal age at delivery; maternal social class; maternal first trimester smoking; abstinence time; place of semen sample collection (not testes volume); spillage (not testes volume). Motility further adjusted for interval between ejaculation and analysis in minutes. Due to model fit, the figure show results for NP (non-progressive) + IM (immotile) spermatozoa. Therefore, negative estimates represent a higher proportion of progressive motility, and positive estimates represent a lower proportion of progressive motility. Point estimates with 95% confidence intervals are shown to the right.

Figure 3 Main results exploring the timing of parental separation in childhood. Relative percentage differences in semen quality and testes volume according to timing of parental separation in childhood (N=696). Parental separation from birth (square and black), in early childhood (circle and dark grey) or in late childhood (triangle and light grey) relatively to no parental separation (vertical line). Adjusted for maternal age at delivery; maternal social class; maternal first trimester smoking; abstinence time; place of semen sample collection (not testes volume); spillage (not testes volume). Motility further adjusted for interval between ejaculation and analysis in minutes. Due to model fit, the figure show results for NP (non-progressive) + IM (immotile) spermatozoa. Therefore, negative estimates represent a higher proportion of progressive motility, and positive estimates represent a lower proportion of progressive motility. Point estimates with 95% confidence intervals are shown to the right.