IGF-1
IGF-1 falls through adult life, so reference intervals are set by age and sex, and they differ between assays, mostly at the upper limit. Both low and high levels go with more deaths in pooled cohorts, and higher levels with more breast and prostate cancer. Growth hormone trials in older adults shifted body composition slightly and raised adverse events.
- Status
- A blood test ordered by a clinician and also sold direct to consumers by some US laboratories.
- Measures
- The amount of insulin-like growth factor 1 in blood, a hormone that manages the effects of growth hormone and is more stable through the day than growth hormone itself [1].
- Also called
- IGF-1, IGF-I, IGF1, insulin-like growth factor 1, insulin-like growth factor I, somatomedin C, somatomedin C test, IGF-1 test
- Tested for
- growth hormone deficiency, acromegaly, growth problems in children, monitoring growth hormone therapy, aging, muscle growth, recovery
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Linked in research4
- StrongLinked to more deaths at both low and high levels in two pooled analyses, 27% to 33% more at low levels and 18% to 23% more at high levels.
- StrongShown in genetic and cohort studies to go with more breast cancer at higher levels, 28% more in the top fifth than the bottom fifth across 17 studies.
- ModerateLinked to more prostate cancer at higher levels, 29% more in the top fifth across pooled prospective studies, with mixed directions for other cancer sites.
- ModerateLinked to mortality in acromegaly: deaths were near expected when treatment brought IGF-1 into the normal range, and 2.5 times expected when it stayed raised.
Reported risks0
No risks sourced yet.
Reference ranges
Each range is the one its source published, in ng/mL. Where sources differ, each is shown.
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 18 to 20
Men aged 18 to 20, measured with the IDS-iSYS immunoassay · [2], [3]
| Range | What the source calls it |
|---|---|
| below 168 ng/mL | "low" |
| 168 to 391 ng/mL | "normal" |
| above 391 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 56 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 168 to 197 ng/mL and upper limits of 374 to 537 ng/mL. The table covers 899 of the 911 adults aged 18 to 89 from the French general population whom the study classed as healthy (mean body mass index 23.0). The study sorts results into low, normal or high against these two percentiles. The authors report that their limits ran slightly higher, and their intervals narrower, than those of a 15,014-person study that used the same assay [2][3].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 21 to 23
Men aged 21 to 23, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 147 ng/mL | "low" |
| 147 to 346 ng/mL | "normal" |
| above 346 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 61 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 150 to 173 ng/mL and upper limits of 337 to 477 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 24 to 26
Men aged 24 to 26, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 132 ng/mL | "low" |
| 132 to 313 ng/mL | "normal" |
| above 313 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 53 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 135 to 155 ng/mL and upper limits of 308 to 430 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 27 to 29
Men aged 27 to 29, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 122 ng/mL | "low" |
| 122 to 292 ng/mL | "normal" |
| above 292 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 49 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 126 to 143 ng/mL and upper limits of 289 to 396 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 30 to 39
Men aged 30 to 39, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 108 ng/mL | "low" |
| 108 to 265 ng/mL | "normal" |
| above 265 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 56 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 112 to 127 ng/mL and upper limits of 265 to 348 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 40 to 49
Men aged 40 to 49, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 91 ng/mL | "low" |
| 91 to 233 ng/mL | "normal" |
| above 233 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 51 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 97 to 107 ng/mL and upper limits of 237 to 301 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 50 to 59
Men aged 50 to 59, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 81 ng/mL | "low" |
| 81 to 214 ng/mL | "normal" |
| above 214 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 54 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 85 to 97 ng/mL and upper limits of 218 to 273 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 60 to 69
Men aged 60 to 69, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 75 ng/mL | "low" |
| 75 to 208 ng/mL | "normal" |
| above 208 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 49 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 77 to 92 ng/mL and upper limits of 214 to 260 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, men aged 70 to 89
Men aged 70 to 89, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 64 ng/mL | "low" |
| 64 to 192 ng/mL | "normal" |
| above 192 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 34 men of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 66 to 80 ng/mL and upper limits of 200 to 242 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 18 to 20
Women aged 18 to 20, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 155 ng/mL | "low" |
| 155 to 421 ng/mL | "normal" |
| above 421 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 41 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 161 to 191 ng/mL and upper limits of 412 to 586 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 21 to 23
Women aged 21 to 23, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 144 ng/mL | "low" |
| 144 to 383 ng/mL | "normal" |
| above 383 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 54 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 149 to 176 ng/mL and upper limits of 379 to 541 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 24 to 26
Women aged 24 to 26, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 134 ng/mL | "low" |
| 134 to 353 ng/mL | "normal" |
| above 353 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 45 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 139 to 163 ng/mL and upper limits of 353 to 501 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 27 to 29
Women aged 27 to 29, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 126 ng/mL | "low" |
| 126 to 330 ng/mL | "normal" |
| above 330 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 48 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 131 to 152 ng/mL and upper limits of 332 to 467 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 30 to 39
Women aged 30 to 39, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 113 ng/mL | "low" |
| 113 to 294 ng/mL | "normal" |
| above 294 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 47 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 118 to 131 ng/mL and upper limits of 298 to 403 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 40 to 49
Women aged 40 to 49, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 97 ng/mL | "low" |
| 97 to 253 ng/mL | "normal" |
| above 253 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 50 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 98 to 109 ng/mL and upper limits of 258 to 331 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 50 to 59
Women aged 50 to 59, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 80 ng/mL | "low" |
| 80 to 209 ng/mL | "normal" |
| above 209 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 54 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 80 to 97 ng/mL and upper limits of 220 to 271 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 60 to 69
Women aged 60 to 69, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 64 ng/mL | "low" |
| 64 to 170 ng/mL | "normal" |
| above 170 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 47 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 68 to 84 ng/mL and upper limits of 190 to 227 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
VARIETE cohort, Chanson and colleagues, 2016, iSYS assay, women aged 70 to 89
Women aged 70 to 89, measured with the IDS-iSYS immunoassay · [2]
| Range | What the source calls it |
|---|---|
| below 56 ng/mL | "low" |
| 56 to 154 ng/mL | "normal" |
| above 154 ng/mL | "high" |
The 2.5th and 97.5th percentiles in 50 women of this age, measured with the iSYS immunoassay (IDS), which is calibrated against the WHO standard 02/254. On the same samples the other five assays tested gave lower limits of 60 to 81 ng/mL and upper limits of 175 to 204 ng/mL. See the block for men aged 18 to 20 for how the study was done [2].
What has been shown to move it
Shown to raise it3
Lean mass and leg strength in orthopedic patients
Shown to raise lean body mass about 3.6% and leg strength about 3.2% in orthopedic and sports medicine patients.
IGF-1 rose by a mean of 133.2%, in a dose-dependent way.
The numbers and sources
- Effect
- Across orthopedic studies, lean body mass rose in 15 of 23 studies, a mean difference of 3.63% against placebo, and leg extension strength rose by a mean difference of 3.17%. IGF-1 rose by a mean of 133.2%, in a dose-dependent way [5].
- Population
- 1,157 patients, mean age 54.3, in 22 studies of orthopedic surgery and sports medicine settings, mean dose 1.49 mg per day [5].
- Sources
- [5]
- Caveats
- The review rated its studies as moderate quality and pooled only where it could [5]. These were patients, not healthy athletes.
Growth hormone and IGF-1 levels
Small trials found single injections of CJC-1295 raised growth hormone and IGF-1 for days in healthy adults. No study measured muscle, fat, sleep or recovery.
The numbers and sources
- Effect
- In two randomized, placebo-controlled, double-blind, ascending-dose trials, a single injection of CJC-1295 raised mean plasma growth hormone 2- to 10-fold for 6 days or more and mean IGF-1 1.5- to 3-fold for 9 to 11 days, rising with dose. After multiple doses, mean IGF-1 stayed above baseline for up to 28 days [1]. In healthy men measured before and 1 week after one injection, trough growth hormone rose 7.5-fold, mean growth hormone 46% and IGF-1 45%, while the frequency and size of growth hormone pulses did not change [2]. In healthy men given intravenous ipamorelin at five dose levels, every dose produced a single episode of growth hormone release that peaked at 0.67 hours and fell to negligible levels [3].
- Population
- Healthy adults aged 21 to 61, in trials lasting 28 and 49 days. The abstract does not give the number enrolled [1]. Healthy men aged 20 to 40 [2]. 40 healthy men, 8 at each dose level [3].
- Sources
- [1], [2], [3]
- Caveats
- Growth hormone and IGF-1 are laboratory measures. None of these studies reported muscle, fat, sleep or recovery. The study in [2] had no placebo group, and the abstract of [3] does not describe one. Each peptide was tested alone, not the two combined.
Raised IGF-1 and a cancer warning
The label warns of an increased risk of neoplasms and lists active cancer as a contraindication. IGF-1 rose 81% in one trial.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- IGF-1 rose 81.0% on tesamorelin and fell 5.0% on placebo [1]. The label states the effects of prolonged IGF-1 elevation are unknown, warns of an increased risk of neoplasms, and lists active malignancy as a contraindication [6].
- Population
- 412 adults with HIV [1]; label [6].
- Sources
- [1], [6]
- Caveats
- The cancer warning is a label precaution. The sourced trials did not report cancer rates.
Tested, and not shown to change it3
Growth hormone and muscle growth
Mixed results: small trials found oral arginine raised resting growth hormone but blunted its rise after lifting, and lean mass did not change in athletes over 45 days.
In 14 strength-trained men, arginine before lifting blunted growth hormone (area under the curve 288.4 against 487.9 on placebo, p < 0.05), with no difference in IGF-1.
The numbers and sources
- Effect
- In 8 healthy men, 5 g and 9 g of oral arginine raised the growth hormone area under the curve over placebo at rest, while 13 g did not and caused stomach upset in most [16]. In 8 men, 7 g of arginine before resistance exercise gave a smaller growth hormone response than exercise alone [17]. In 14 strength-trained men, arginine before lifting blunted growth hormone (area under the curve 288.4 against 487.9 on placebo, p < 0.05), with no difference in IGF-1 [18]. In 56 male soccer players, 2 g a day for 45 days did not change lean body mass, fat mass or BMI against placebo [19].
- Population
- Healthy young men [16][17]. Strength-trained men [18]. Male soccer players aged 16 to 35 [19].
- Sources
- [16], [17], [18], [19]
- Caveats
- Small, short trials in men. Growth hormone was measured for hours after a single dose, and no trial measured muscle growth over a training program [16][17][18].
Strength in older men
One small study without placebo found 2 of 6 strength measures improved over 6 weeks in men aged 64 to 76. Muscle mass did not change.
The numbers and sources
- Effect
- Over 6 weeks, nightly sermorelin raised nighttime growth hormone release, with no change in IGF-1. Two of six strength measures (upright row and shoulder press) and one endurance test (abdominal crunch) improved. Muscle by DEXA and muscle histology did not change [4].
- Population
- 11 healthy, non-obese men aged 64 to 76 with low baseline IGF-1 [4].
- Sources
- [4]
- Caveats
- One small study with no placebo group, comparing each man with his own baseline. The authors note that single nightly doses produced smaller hormone effects than multiple daily doses in earlier work [4].
Muscle growth with turkesterone
One small study found no significant change in IGF-1 or resting metabolic rate within 24 hours of turkesterone in 11 young men. No muscle growth trial was located.
Compared with placebo [8]
IGF-1 rose non-significantly on both turkesterone conditions.
The numbers and sources
- Effect
- In 11 healthy men, mean age 23, turkesterone did not significantly change serum IGF-1, resting metabolic rate, or blood lipid and carbohydrate measures at 3 or 24 hours against placebo. IGF-1 rose non-significantly on both turkesterone conditions [8].
- Population
- 11 healthy young men, with samples before and 3 and 24 hours after doses [8].
- Sources
- [8]
- Caveats
- One small, short study of single doses. IGF-1 and metabolic rate are markers, not muscle growth, and no training was involved [8]. Tested turkesterone products often held little or none of the labeled ingredient (see Risks) [4].
How it compares with the reference method
Mixed results2
Agreement between assays
One study found six IGF-1 immunoassays run on the same adults gave similar lower limits and widely different upper limits, and classed 94% to 97% of results alike.
The numbers and sources
- Compared with
- Five other IGF-1 immunoassays run on the same samples
- Effect
- Six immunoassays measured the same samples from 911 adults. The lower limits of the reference intervals were similar and the upper limits varied markedly. In men aged 18 to 20, for example, the upper limit ran from 374 ng/mL on one assay to 537 on another. Agreement between pairs of assays on whether a result was low, normal or high had a weighted kappa of 0.38 to 0.70, which the authors describe as moderate to good, with 94% to 97% of results classed the same way. The two assays calibrated against an older international standard gave the highest upper limits up to age 50. Agreement between the study's intervals and the ones each manufacturer supplies was generally poor [2]. The authors of a 15,014-person reference study for one of these assays also describe considerable discrepancies between methods [3].
- Population
- 911 adults aged 18 to 90 in the French general population [2].
- Sources
- [2], [3]
- Caveats
- One study. The ranges on this page are for the iSYS assay only, and a result from another assay may be classed differently against them [2].
Variation from one test to the next
Small studies found IGF-1 varied about 9% within a person over six weeks and 14% to 16% within athletes over up to a year.
The numbers and sources
- Compared with
- The same person's earlier results
- Effect
- In 10 subjects sampled weekly for six weeks, the within-person variation of IGF-1 was 9.4% [13]. In four studies of athletes sampled over up to 12 months, it was 14% to 16%, with no apparent difference between amateur and elite athletes [14].
- Population
- 10 subjects [13]. 303 elite and 78 amateur athletes aged 17 to 53, 238 men and 143 women [14].
- Sources
- [13], [14]
- Caveats
- The first study had 10 people. The second studied athletes for an anti-doping test [14].
What studies tie it to
Linked in research4
Death from any cause
Linked to more deaths at both low and high levels in two pooled analyses, 27% to 33% more at low levels and 18% to 23% more at high levels.
The numbers and sources
- Effect
- In a meta-analysis of 12 studies, people with low IGF-1 had a hazard ratio for death from any cause of 1.27 (95% CI 1.08 to 1.49) and people with high IGF-1 had 1.18 (1.04 to 1.34), each against the middle of the distribution. The relation was U-shaped, and it held for both cancer deaths and cardiovascular deaths. The predicted hazard ratio was 1.56 (1.31 to 1.86) for the 10th percentile against the 50th, and 1.29 (1.06 to 1.58) for the 90th against the 50th [4]. A later meta-analysis of 19 cohorts found 1.33 (1.14 to 1.57) for low against middle levels and 1.23 (1.06 to 1.44) for high against middle, with the lowest mortality at 120 to 160 ng/mL [5].
- Population
- 14,906 participants in 12 studies [4]. 30,876 adults in 19 prospective cohorts [5].
- Sources
- [4], [5]
- Caveats
- Observational. The cohorts used different assays, and results from different assays differ, most of all at the upper end [2], so the 120 to 160 ng/mL figure is not tied to any one laboratory's result. The later analysis notes that low IGF-1 may reflect frailty and illness already present [5].
Breast cancer
Shown in genetic and cohort studies to go with more breast cancer at higher levels, 28% more in the top fifth than the bottom fifth across 17 studies.
The numbers and sources
- Effect
- In pooled individual data from 17 prospective studies, women in the highest fifth of IGF-1 had an odds ratio for breast cancer of 1.28 (95% CI 1.14 to 1.44) against the lowest fifth. The association was 1.38 (1.14 to 1.68) for estrogen receptor positive tumors and 0.80 (0.57 to 1.13) for estrogen receptor negative tumors [6]. In UK Biobank, each 5 nmol/L higher IGF-1 had a hazard ratio of 1.11 (1.07 to 1.16), and each 5 nmol/L of genetically predicted IGF-1 had an odds ratio of 1.05 (1.01 to 1.10) [7].
- Population
- 4,790 women with breast cancer and 9,428 matched controls in 12 countries [6]. 206,263 women followed for a median 7.1 years, and genetic data on 122,977 cases and 105,974 controls [7].
- Sources
- [6], [7]
- Caveats
- The cohort findings are observational. Genetic estimates describe lifelong differences, not the effect of changing the level later in life. The second study reports IGF-1 in nmol/L, a unit this page does not convert.
Prostate cancer and other cancers
Linked to more prostate cancer at higher levels, 29% more in the top fifth across pooled prospective studies, with mixed directions for other cancer sites.
The numbers and sources
- Effect
- In pooled individual data from prospective studies, men in the highest fifth of IGF-1 had an odds ratio for prostate cancer of 1.29 (95% CI 1.16 to 1.43) against the lowest fifth, and the association did not differ by time to diagnosis or by tumor stage or grade [8]. In UK Biobank, each 5 nmol/L higher IGF-1 had a hazard ratio of 1.03 for cancer overall in both men and women (1.01 to 1.06), 1.10 for breast, 1.09 for prostate, 1.07 for colorectal and 1.22 for thyroid cancer. It was 0.91 for lung, 0.86 for ovarian and 0.32 for liver cancer [9].
- Population
- Up to 10,554 men with prostate cancer and 13,618 controls in 17 prospective and 2 cross-sectional studies [8]. 412,645 adults followed for a median 7.2 years [9].
- Sources
- [8], [9]
- Caveats
- Observational. The inverse association with lung cancer appeared only in people who had ever smoked [9].
Death in acromegaly after treatment that lowered IGF-1
Linked to mortality in acromegaly: deaths were near expected when treatment brought IGF-1 into the normal range, and 2.5 times expected when it stayed raised.
The numbers and sources
- Effect
- In a meta-analysis of mortality studies in acromegaly, a condition of excess growth hormone, people whose IGF-1 was normal for age and sex at last follow-up after treatment had a standardized mortality ratio of 1.1 (95% CI 0.9 to 1.4). People whose IGF-1 stayed raised had 2.5 (1.6 to 4.0) [12].
- Population
- Published mortality series in acromegaly from 1965 to 2008 that reported deaths by hormone level at last follow-up [12].
- Sources
- [12]
- Caveats
- Observational comparisons within a rare disease, not randomized. People whose IGF-1 came down may have differed in other ways from those in whom it did not.
Mixed results1
Body composition and adverse events in trials of growth hormone
Shown in trials of growth hormone to shift fat and lean mass by about 2 kg in older adults, with more swelling, joint pain and carpal tunnel syndrome.
The numbers and sources
- Effect
- IGF-1 manages the effects of growth hormone in the body [1], and these trials gave growth hormone without aiming at an IGF-1 level. In community-dwelling adults with a mean age of 69 who were not being treated for a specific illness, growth hormone lowered fat mass by 2.1 kg (95% CI 1.35 to 2.8) and raised lean mass by 2.1 kg (1.3 to 2.9), with no change in weight, bone density or most blood lipids. Treated people were more likely to have soft tissue swelling, joint pain, carpal tunnel syndrome and breast growth in men, and somewhat more likely to develop diabetes or impaired fasting glucose [10]. In adults with confirmed growth hormone deficiency, it lowered weight by 2.31 kg (1.96 to 2.66) and body fat by 2.56 kg (2.16 to 2.97) and raised lean mass by 1.38 kg (1.10 to 1.65). Swelling had a relative risk of 6.07 (4.34 to 8.48) and joint stiffness 4.17 (1.4 to 12.38), with no significant change in bone density. Quality of life improved in 11 of 16 trials [11].
- Population
- 220 treated participants in 18 study populations, mean treatment 27 weeks [10]. More than 3,400 patients in 54 randomized trials [11].
- Sources
- [10], [11], [1]
- Caveats
- A marker that tracks an outcome is not always one whose correction changes it. Low IGF-1 went with more deaths in cohorts, and these trials measured body composition, not deaths. The trials in older adults were small and short [10].
Sources
- US National Library of Medicine. IGF-1 (Insulin-like Growth Factor 1) Test. MedlinePlus Medical Tests. Last updated September 24, 2024. https://medlineplus.gov/lab-tests/igf-1-insulin-like-growth-factor-1-test/
- Chanson P, Arnoux A, Mavromati M, et al. Reference Values for IGF-I Serum Concentrations: Comparison of Six Immunoassays. The Journal of Clinical Endocrinology and Metabolism. 2016. https://doi.org/10.1210/jc.2016-1257
- Bidlingmaier M, Friedrich N, Emeny RT, et al. Reference Intervals for Insulin-like Growth Factor-1 (IGF-I) From Birth to Senescence: Results From a Multicenter Study Using a New Automated Chemiluminescence IGF-I Immunoassay Conforming to Recent International Recommendations. The Journal of Clinical Endocrinology and Metabolism. 2014. https://doi.org/10.1210/jc.2013-3059
- Burgers AMG, Biermasz NR, Schoones JW, et al. Meta-Analysis and Dose-Response Metaregression: Circulating Insulin-Like Growth Factor I (IGF-I) and Mortality. The Journal of Clinical Endocrinology and Metabolism. 2011. https://doi.org/10.1210/jc.2011-1377
- Rahmani J, Montesanto A, Giovannucci E, et al. Association between IGF-1 levels ranges and all-cause mortality: A meta-analysis. Aging Cell. 2022. https://doi.org/10.1111/acel.13540
- Endogenous Hormones and Breast Cancer Collaborative Group, Key TJ, Appleby PN, Reeves GK, Roddam AW. Insulin-like growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), and breast cancer risk: pooled individual data analysis of 17 prospective studies. The Lancet Oncology. 2010. https://doi.org/10.1016/s1470-2045(10)70095-4
- Murphy N, Knuppel A, Papadimitriou N, et al. Insulin-like growth factor-1, insulin-like growth factor-binding protein-3, and breast cancer risk: observational and Mendelian randomization analyses with about 430 000 women. Annals of Oncology. 2020. https://doi.org/10.1016/j.annonc.2020.01.066
- Travis RC, Appleby PN, Martin RM, et al. A Meta-analysis of Individual Participant Data Reveals an Association between Circulating Levels of IGF-I and Prostate Cancer Risk. Cancer Research. 2016. https://doi.org/10.1158/0008-5472.can-15-1551
- Qian F, Huo D. Circulating Insulin-Like Growth Factor-1 and Risk of Total and 19 Site-Specific Cancers: Cohort Study Analyses from the UK Biobank. Cancer Epidemiology, Biomarkers and Prevention. 2020. https://doi.org/10.1158/1055-9965.epi-20-0743
- Liu H, Bravata DM, Olkin I, et al. Systematic Review: The Safety and Efficacy of Growth Hormone in the Healthy Elderly. Annals of Internal Medicine. 2007. https://doi.org/10.7326/0003-4819-146-2-200701160-00005
- Hazem A, Elamin MB, Bancos I, et al. Body composition and quality of life in adults treated with GH therapy: a systematic review and meta-analysis. European Journal of Endocrinology. 2012. https://doi.org/10.1530/EJE-11-0558
- Holdaway IM, Bolland MJ, Gamble GD. A meta-analysis of the effect of lowering serum levels of GH and IGF-I on mortality in acromegaly. European Journal of Endocrinology. 2008. https://doi.org/10.1530/eje-08-0267
- Ankrah-Tetteh T, Wijeratne S, Swaminathan R. Intraindividual variation in serum thyroid hormones, parathyroid hormone and insulin-like growth factor-1. Annals of Clinical Biochemistry. 2008. https://doi.org/10.1258/acb.2007.007103
- Erotokritou-Mulligan I, Bassett EE, Cowan DA, et al. The use of growth hormone (GH)-dependent markers in the detection of GH abuse in sport: Physiological intra-individual variation of IGF-I, type 3 pro-collagen (P-III-P) and the GH-2000 detection score. Clinical Endocrinology. 2010. https://doi.org/10.1111/j.1365-2265.2009.03668.x