Food Sci Clin Nutr

Food Sciences and Clinical Nutrition, ISSN 0000-0000 online, Open Access

Article copyright, the authors; Journal compilation copyright, Food Sci Clin Nutr and Elmer Press Inc

Journal website https://fscn.elmerpub.com

Original Article

Volume 1, June 2026, e4

Age- and Time-Related Changes in Serum Ferritin in Danish Men: A Population-Based Longitudinal Study of 1,199 Men Over a 10-Year Period: Influence of Nutritional Factors

↓ **Table 1.** Measurements of Hemoglobin in All Men in the MONICA Cohort
	Age, years	Willcoxon test paired samples	Friedman test paired samples
The men were examined in MONICA 1, and 990 of them in MONICA 10 as well. ^aValues above and below the reference interval for Danish men; Willcoxon test paired samples and Friedman test compare values in men examined in both surveys. IQR: interquartile range; ns: not significant; SD: standard deviation.
Hemoglobin, g/L			P < 0.0001	P < 0.00001
Mean ± SD	154 ± 7.1	153 ± 10	n = 990	n = 990
Median (IQR)	155 (148–161)	152 (145–158)
Age, years	30–60	40–70	Fisher’s exact test
Hemoglobin > 169 g/L^a	n = 69 5.8%	n = 19 1.9%	P < 0.0001
Hemoglobin < 134 g/L^a	n = 31 2.6%	n = 25 2.5%	ns

↓ Table 1. Measurements of Hemoglobin in All Men in the MONICA Cohort

Age, years

Willcoxon test paired samples

Friedman test paired samples

MONICA 1 (n = 1,199)
30–60, median 40

MONICA 10 (n = 990)
40–70, median 50

The men were examined in MONICA 1, and 990 of them in MONICA 10 as well. ^aValues above and below the reference interval for Danish men; Willcoxon test paired samples and Friedman test compare values in men examined in both surveys. IQR: interquartile range; ns: not significant; SD: standard deviation.

Hemoglobin, g/L

P < 0.0001

P < 0.00001

Mean ± SD

154 ± 7.1

153 ± 10

n = 990

Median (IQR)

155 (148–161)

152 (145–158)

Age, years

30–60

40–70

Fisher’s exact test

Hemoglobin > 169 g/L^a

n = 69
5.8%

n = 19
1.9%

P < 0.0001

Hemoglobin < 134 g/L^a

n = 31
2.6%

n = 25
2.5%

↓ **Table 2.** Longitudinal Measurements of Serum Ferritin in All Men in the MONICA Cohort
	Age, years	Willcoxon test paired samples	Friedman test paired samples
The men were invited for examination three times. All were examined in MONICA 1, and the majority subsequently in MONICA 5 and/or MONICA 10, i.e., all had at least two measurements of ferritin. Friedman test compares values in men examined in all three surveys. IQR: interquartile range; SD: standard deviation.
Ferritin, µg/L, median (IQR)	125 (75–195)	143 (90–229)	156 (96–245)	1 vs. 5: P < 0.0001, n = 1,014 5 vs. 10: P < 0.0001, n = 806	P < 0.00001, n = 806
Geometric mean	116	139	151	Chi-square test
Ferritin > 300 µg/L	n = 97 8.1%	n = 135 13.3%	n = 167 16.9%	P < 0.0001
Ferritin < 30 µg/L	n = 63 5.3%	n = 38 3.7%	n = 28 2.8%	P = 0.014

↓ Table 2. Longitudinal Measurements of Serum Ferritin in All Men in the MONICA Cohort

Age, years

Willcoxon test paired samples

Friedman test paired samples

MONICA 1 (n = 1,199)
30–60, median 40

MONICA 5 (n = 1,014)
35–65, median 45

MONICA 10 (n = 991)
40–70, median 50

The men were invited for examination three times. All were examined in MONICA 1, and the majority subsequently in MONICA 5 and/or MONICA 10, i.e., all had at least two measurements of ferritin. Friedman test compares values in men examined in all three surveys. IQR: interquartile range; SD: standard deviation.

Ferritin, µg/L, median (IQR)

125 (75–195)

143 (90–229)

156 (96–245)

1 vs. 5: P < 0.0001, n = 1,014
5 vs. 10: P < 0.0001, n = 806

P < 0.00001, n = 806

Geometric mean

116

139

151

Chi-square test

Ferritin > 300 µg/L

n = 97
8.1%

n = 135
13.3%

n = 167
16.9%

P < 0.0001

Ferritin < 30 µg/L

n = 63
5.3%

n = 38
3.7%

n = 28
2.8%

P = 0.014

↓ **Table 3.** The Number of Blood Donors in Men According to Age in MONICA 1 and MONICA 10 Surveys
Age, years	MONICA 1	Age, years	MONICA 10	Fisher’s exact test
30	n = 76/295 25.8%	40	n = 52/261 19.9%	P = 0.3
40	n = 102/327 31.2%	50	n = 50/278 18.0%	P = 0.002
50	n = 84/309 27.2%	60	n = 28/258 10.9%	P < 0.0001
60	n = 72/268 26.9%	70	n = 11/192 5.7%	P < 0.0001
Total	n = 334/1,199 27.9%	Total	n = 141/989 14.3%	P < 0.0001

↓ Table 3. The Number of Blood Donors in Men According to Age in MONICA 1 and MONICA 10 Surveys

Age, years

MONICA 1

Age, years

MONICA 10

Fisher’s exact test

n = 76/295
25.8%

n = 52/261
19.9%

P = 0.3

n = 102/327
31.2%

n = 50/278
18.0%

P = 0.002

n = 84/309
27.2%

n = 28/258
10.9%

P < 0.0001

n = 72/268
26.9%

n = 11/192
5.7%

P < 0.0001

Total

n = 334/1,199
27.9%

Total

n = 141/989
14.3%

P < 0.0001

↓ **Table 4.** Longitudinal Measurements of Serum Ferritin in Men, Blood Donors, in the MONICA Cohort
	MONICA 1 (n = 334)	MONICA 5 (n = 288)	MONICA 10 (n = 276)	Willcoxon test paired samples	Friedman test paired samples
The men were invited for examination three times. All were examined in MONICA 1, and the majority subsequently in MONICA 5 and/or MONICA 10, i.e., all had at least two measurements of ferritin. Friedman test compares values in men examined in all three surveys. ^aCompared with ferritin in non-blood-donors: Mann–Whitney test, P < 0.0001. IQR: interquartile range; SD: standard deviation.
Ferritin, µg/L, median (IQR)	88 (44–155)^a	112 (68–192)^a	125 (65–206)^a	1 vs. 5: P < 0.0001, n = 288 5 vs. 10: P < 0.0001, n = 230	P < 0.00001, n = 230
Geometric mean	81	111	120	Chi-square test
Ferritin > 300 µg/L	n = 20 6.0%	n = 32 11.1%	n = 38 13.8%	P = 0.005
Ferritin < 30 µg/L	n = 44 13.2%	n = 23 8.0%	n = 15 5.4%	P = 0.001

↓ Table 4. Longitudinal Measurements of Serum Ferritin in Men, Blood Donors, in the MONICA Cohort

MONICA 1 (n = 334)

MONICA 5 (n = 288)

MONICA 10 (n = 276)

Willcoxon test paired samples

Friedman test paired samples

Ferritin, µg/L, median (IQR)

88 (44–155)^a

112 (68–192)^a

125 (65–206)^a

1 vs. 5: P < 0.0001, n = 288
5 vs. 10: P < 0.0001, n = 230

P < 0.00001, n = 230

Geometric mean

111

120

Chi-square test

Ferritin > 300 µg/L

n = 20
6.0%

n = 32
11.1%

n = 38
13.8%

P = 0.005

Ferritin < 30 µg/L

n = 44
13.2%

n = 23
8.0%

n = 15
5.4%

P = 0.001

↓ **Table 5.** Longitudinal Measurements of Serum Ferritin in Men, Non-Blood-Donors, in the MONICA Cohort
	MONICA 1 (n = 865)	MONICA 5 (n = 726)	MONICA 10 (n = 715)	Willcoxon test paired samples	Friedman test paired samples
The men were invited for examination three times. All were examined in MONICA 1, and the majority subsequently examined in MONICA 5 and/or MONICA 10, i.e., all had at least two measurements of ferritin. Friedman test compares values in men examined in all three surveys. ^aCompared with ferritin in blood donors: Mann–Whitney test, P < 0.0001. IQR: interquartile range; SD: standard deviation.
Ferritin, µg/L, median (IQR)	136 (89–206)^a	154 (100–237)^a	168 (107–286)^a	1 vs. 5: P < 0.0001, n = 726 5 vs. 10: P < 0.0001, n = 576	P < 0.00001, n = 576
Geometric mean	134	153	164	Chi-square test
Ferritin > 300 µg/L	n = 77 8.9%	n = 103 14.2%	n = 129 18.0%	P < 0.0001
Ferritin < 30 µg/L	n = 15 1.7%	n = 15 2.1%	n = 14 2.0%	P = 0.7

↓ Table 5. Longitudinal Measurements of Serum Ferritin in Men, Non-Blood-Donors, in the MONICA Cohort

MONICA 1 (n = 865)

MONICA 5 (n = 726)

MONICA 10 (n = 715)

Willcoxon test paired samples

Friedman test paired samples

The men were invited for examination three times. All were examined in MONICA 1, and the majority subsequently examined in MONICA 5 and/or MONICA 10, i.e., all had at least two measurements of ferritin. Friedman test compares values in men examined in all three surveys. ^aCompared with ferritin in blood donors: Mann–Whitney test, P < 0.0001. IQR: interquartile range; SD: standard deviation.

Ferritin, µg/L, median (IQR)

136 (89–206)^a

154 (100–237)^a

168 (107–286)^a

1 vs. 5: P < 0.0001, n = 726
5 vs. 10: P < 0.0001, n = 576

P < 0.00001, n = 576

Geometric mean

134

153

164

Chi-square test

Ferritin > 300 µg/L

n = 77
8.9%

n = 103
14.2%

n = 129
18.0%

P < 0.0001

Ferritin < 30 µg/L

n = 15
1.7%

n = 15
2.1%

n = 14
2.0%

P = 0.7

↓ **Table 6.** Longitudinal Measurements of Serum Ferritin (Median and Interquartile Range) in Men, Non-Blood-Donors, in the MONICA Cohort, Arranged According to Age at Inclusion in MONICA 1
	Ferritin	Willcoxon test paired samples	Friedman test paired samples
The men were invited for examination three times. All were examined in MONICA 1, and the majority subsequently in MONICA 5 and/or MONICA 10, i.e., all had at least two measurements of ferritin. Friedman test compares values in men examined in all three surveys.
Age, years	128 (94–184) n = 219 30	145 (99–201) n = 185 35	168 (112–245) n = 196 40	1 vs. 5: P < 0.0001, n = 185 5 vs. 10: P < 0.0001, n = 162	P < 0.00001 n = 162
Age, years	136 (83–199) n = 225 40	163 (104–252) n = 186 45	163 (103–277) n = 188 50	1 vs. 5: P < 0.0001, n = 186 5 vs. 10: P = 0.01, n = 149	P < 0.00001 n = 149
Age, years	150 (89–214) n = 225 50	164 (99–249) n = 188 55	183 (118–269) n = 187 60	1 vs. 5: P < 0.0001, n = 188 5 vs. 10: P = 0.01, n = 150	P < 0.00001 n = 150
Age, years	135 (85–229) n = 196 60	150 (102–245) n = 167 65	151 (88–252) n = 144 70	1 vs. 5: P = 0.06, n =167 5 vs. 10: P = 0.2, n = 115	P = 0.2 n = 115
Kruskal–Wallis test ANOVA F-test	P = 0.3 P = 0.2	P = 0.4 P = 0.2	P = 0.08 P = 0.2

↓ Table 6. Longitudinal Measurements of Serum Ferritin (Median and Interquartile Range) in Men, Non-Blood-Donors, in the MONICA Cohort, Arranged According to Age at Inclusion in MONICA 1

Ferritin

Willcoxon test paired samples

Friedman test paired samples

MONICA 1

MONICA 5

MONICA 10

Age, years

128 (94–184)
n = 219
30

145 (99–201)
n = 185
35

168 (112–245)
n = 196
40

1 vs. 5: P < 0.0001, n = 185
5 vs. 10: P < 0.0001, n = 162

P < 0.00001
n = 162

Age, years

136 (83–199)
n = 225
40

163 (104–252)
n = 186
45

163 (103–277)
n = 188
50

1 vs. 5: P < 0.0001, n = 186
5 vs. 10: P = 0.01, n = 149

P < 0.00001
n = 149

Age, years

150 (89–214)
n = 225
50

164 (99–249)
n = 188
55

183 (118–269)
n = 187
60

1 vs. 5: P < 0.0001, n = 188
5 vs. 10: P = 0.01, n = 150

P < 0.00001
n = 150

Age, years

135 (85–229)
n = 196
60

150 (102–245) n = 167
65

151 (88–252) n = 144
70

1 vs. 5: P = 0.06, n =167
5 vs. 10: P = 0.2, n = 115

P = 0.2
n = 115

Kruskal–Wallis test
ANOVA F-test

P = 0.3
P = 0.2

P = 0.4
P = 0.2

P = 0.08
P = 0.2

↓ **Table 7.** Serum Ferritin (Median and Interquartile Range) in Men, Non-Blood Donors, of Same Age, in the MONICA 1 and MONICA 10 Surveys
Age at examination	MONICA 1 1984	MONICA 10 1994	Mann-Whitney test
40 years	n = 225	196
Ferritin, µg/L	136 (83–199)	168 (112–245)	P = 0.0001
50 years	n = 225	188
Ferritin, µg/L	150 (89–214)	163 (103–277)	P = 0.02
60 years	n =196	187
Ferritin, µg/L	135 (85–229)	183 (118–269)	P = 0.001

↓ Table 7. Serum Ferritin (Median and Interquartile Range) in Men, Non-Blood Donors, of Same Age, in the MONICA 1 and MONICA 10 Surveys

Age at examination

MONICA 1
1984

MONICA 10
1994

Mann-Whitney test

40 years

n = 225

196

Ferritin, µg/L

136 (83–199)

168 (112–245)

P = 0.0001

50 years

n = 225

188

Ferritin, µg/L

150 (89–214)

163 (103–277)

P = 0.02

60 years

n =196

187

Ferritin, µg/L

135 (85–229)

183 (118–269)

P = 0.001