Sex Hormone Binding Globulin and Miscarriage
SBHG lower in missed miscarriage
Progesterone, estrogen, total testosterone, and SHBG in 22 patients with missed miscarriage were significantly lower than those in normal group, whereas % free testosterone was significantly higher. There was a significant negative correlation between % free testosterone and SHBG concentration in the normal group, but not in the missed miscarriage group. All the subjects in whom % free testosterone was 1.30% and higher subsequently miscarried, but no subject with % free testosterone less than 0.70% had a miscarriage.
SHBG lower in pregnancies resulting in miscarriage
The median maternal serum SHBG concentration was not significantly different from controls, in those that subsequently developed preeclampsia, non-proteinuric hypertension or preterm delivery. The levels were significantly lower in those with diabetes and those pregnancies resulting in miscarriage.
SHBG lower in pregnancies that miscarry
In general, pregnancies ending in miscarriage displayed lower SHBG-levels than pregnancies with a successful outcome, but a great deal of overlap in SHBG values was found between the miscarriage and the non-miscarriage cases. In the 6th to 9th weeks of pregnancy 'non-pregnant' SHBG levels were frequently found despite normal levels of estrogen in patients continuing pregnancy until delivery. After the 9th gestational week a highly significant positive correlation was found between estrogen and SHBG. The lack of correlation between these parameters before this gestational age indicates that the increased SHBG synthesis seen in pregnancy develops later than the rise in estrogen.
High testosterone/SHBG ratio linked to 15% of recurrent miscarriages
No subject with a testosterone/SHBG ratio of less than .70% had a miscarriage
Total testosterone in 22 patients with missed miscarriage was significantly lower than those in normal group, whereas % free testosterone (the total testosterone level divided by the SHBG level) was significantly higher. There was a significant negative correlation between % free testosterone and SHBG concentration in the normal group, but not in the missed miscarriage group. All the subjects in whom % free testosterone was 1.30% and higher subsequently miscarried, but no subject with % free testosterone less than 0.70% had a miscarriage.
Both testosterone, and the testosterone/SHBG ratio, are higher in recurrent miscarriage
Testosterone concentrations were higher in the women with recurrent miscarriages both with and without PCOS on days LH-7 and LH-4 of the cycle. Concentrations of androstenedione (precursor to testosterone and estrogen) also were higher in the women with recurrent miscarriages, but without PCOS on day LH-7. Testosterone/SHBG ratios were higher in the women with recurrent miscarriages, without PCOS compared with the controls on days LH-7, LH+0, and LH+7.
Raising SHBG Levels
Resistance training boosts SHBG 26%
SHBG increased (from 27.5 to 34.7 nM) whereas testosterone/SHBG decreased significantly (from 1.10 to 0.85). Serum total testosterone and cortisol did not change significantly in a group of 19 elite weight lifters after 20 weeks of training.
Isoflavones increase SHBG by 10%
SHBG significantly increased about 10% with administration of 20 mg or 40 mg isoflavones by tablets, of which 1 g contained 43.5 mg daidzein, 6.0 mg genistein, 24.0 mg glycitein. 17beta-estradiol was decreased throughout the menstruation cycle.
Dietary fiber raises SHBG; Dietary protein lowers SHBG
Dietary sugar lowers SHBG
In the study, exposure to glucose and fructose (monomeric sugar building blocks of carbohydrates) reduced the production of SHGB in vitro by a human liver cell line and in vivo by the liver of mice engineered to express human SHGB.
Flaxseed raises SHBG levels
High BMI associated with low SHBG
Significant inverse correlations were found between estrogen and body mass index (BMI), SHBG and BMI, DHEA-S and dietary fiber, and androstenedione (the precursor of testosterone and estrogen) and protein:carbohydrate ratio.
SHBG is associated with Vitamin D levels
Type of Vitamin E found in food is associated with higher SHBG
Serum SHBG correlated positively with serum HDL-cholesterol, plasma progesterone, and dietary intake of beta-tocopherol, and negatively with that of fructose. Multivariate regression analyses showed that beta-tocopherol and linoleic acid (found in vegetable oils) was an independent positive predictor of serum SHBG. When individual nutrients were the predictor variables, beta-tocopherol, but not other tocopherols or fatty acids (including linoleic acid), was an independent positive predictor of serum SHBG. Circulating insulin and waist circumference, but not serum lipids, were negative independent predictors of SHBG in all regression models. Additional studies are needed in women of other age groups and men to determine whether consumption of foods rich in beta-tocopherol and/or linoleic acid may increase serum SHBG concentrations and may thereby decrease the risk for metabolic syndrome and reproductive organ cancer.
SHBG and Estrogen and Testosterone
Serum SHBG is an an inverse measure of estrogen activity.
Low total testosterone levels were secondary to the low SHBG.
SHBG and Insulin
Low SHBG is associated with up to an 11 fold increased risk of diabetes
Low concentration of SHBG was significantly correlated to the incidence of non-insulin-dependent diabetes mellitus. The increased incidence of diabetes was confined to the lowest quintile of SHBG values, where it was 5-fold higher than in the remaining group. This incidence was further increased to 8- and 11-fold in the lowest 10 and 5% of the values, respectively. We conclude that SHBG is a uniquely strong independent risk factor for the development of non-insulin-dependent diabetes mellitus in women.
SHBG prevents insulin resistance
Our findings suggest that SHBG may account for the inverse association between coffee consumption and type 2 diabetes risk among postmenopausal women. Caffeinated-coffee was positively associated with SHBG but not with sex hormones. Multivariable-adjusted geometric mean levels of SHBG were 26.6 nmol/L among women consuming ≥4 cups/day of caffeinated-coffee and 23.0 nmol/L among non-drinkers . In contrast, neither decaffeinated-coffee nor tea was associated with SHBG or sex hormones. Multivariable-adjusted odds ratio of type 2 diabetes for women consuming ≥4 cups/day of caffeinated-coffee compared with non-drinkers was 0.47. The association was largely attenuated after further adjusting for SHBG (odds ratio=0.71).
High insulin lowers SHBG
There is an inverse relationship between the serum levels of insulin and sex hormone-binding globulin (SHBG) in women. As SHBG is not known to alter the production or metabolism of insulin, whereas insulin has been shown in vitro to decrease the synthesis of SHBG, it seems a reasonable conclusion that the predictable inverse relationship between serum insulin and SHBG indicates that insulin controls SHBG synthesis in vivo.
SHBG level is decreased by high levels of insulin and IGF-1.
SHBG and Thyroid
Hypothyroidism lowers SHBG
Hypothyroidism influences ovarian function by decreasing levels of sex-hormone-binding globulin and increasing the secretion of prolactin.
Testosterone levels were similar, but androstenedione (precursor to testosterone and estrogen) levels were higher and SHBG levels were lower in hirsute women.
Most hormones in the blood are bound by protein carriers—albumin and SHBG.