Lactation Duration and Long-Term Thyroid Function: A Study among Women with Gestational Diabetes

TY - JOUR

T1 - Lactation Duration and Long-Term Thyroid Function

T2 - A Study among Women with Gestational Diabetes

AU - Panuganti, Pranati L

AU - Hinkle, Stefanie N

AU - Rawal, Shristi

AU - Grunnet, Louise G

AU - Lin, Yuan

AU - Liu, Aiyi

AU - Thuesen, Anne C B

AU - Ley, Sylvia H

AU - Olesen, Sjurdur F

AU - Zhang, Cuilin

PY - 2018/7/21

Y1 - 2018/7/21

N2 - Lactation is associated with reduced postpartum weight retention and a lower risk of several cardiometabolic disorders in population-based studies. We examined the association between lactation and long-term thyroid function among women with history of gestational diabetes mellitus (GDM), a high-risk population for subsequent metabolic complications. The study included 550 women who developed GDM in the Danish National Birth Cohort (1996–2002) and followed-up in the Diabetes & Women’s Health Study (2012–2014). We assessed adjusted associations between cumulative lactation duration and concentrations of thyroid stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) measured at follow-up. Women with longer cumulative lactation duration tended to have higher fT3 levels (adjusted β and 95% confidence interval (CI) for ≥12 months vs. none: 0.19 (0.03–0.36); p-trend = 0.05). When restricted to women with a single lifetime pregnancy to control for parity (n = 70), women who lactated for >6 months (vs. none) had higher fT3 levels (0.46 pmol/L (0.12–0.80); p-trend = 0.02) and a higher fT3:fT4 ratio (0.61 (0.17–1.05); p-trend = 0.007). Our findings suggested that a longer duration of lactation may be related to greater serum fT3 levels and fT3:fT4 ratio 9–16 years postpartum among Danish women with a history of GDM. The association was particularly pronounced among women who only had one lifetime pregnancy.

AB - Lactation is associated with reduced postpartum weight retention and a lower risk of several cardiometabolic disorders in population-based studies. We examined the association between lactation and long-term thyroid function among women with history of gestational diabetes mellitus (GDM), a high-risk population for subsequent metabolic complications. The study included 550 women who developed GDM in the Danish National Birth Cohort (1996–2002) and followed-up in the Diabetes & Women’s Health Study (2012–2014). We assessed adjusted associations between cumulative lactation duration and concentrations of thyroid stimulating hormone (TSH), free triiodothyronine (fT3), and free thyroxine (fT4) measured at follow-up. Women with longer cumulative lactation duration tended to have higher fT3 levels (adjusted β and 95% confidence interval (CI) for ≥12 months vs. none: 0.19 (0.03–0.36); p-trend = 0.05). When restricted to women with a single lifetime pregnancy to control for parity (n = 70), women who lactated for >6 months (vs. none) had higher fT3 levels (0.46 pmol/L (0.12–0.80); p-trend = 0.02) and a higher fT3:fT4 ratio (0.61 (0.17–1.05); p-trend = 0.007). Our findings suggested that a longer duration of lactation may be related to greater serum fT3 levels and fT3:fT4 ratio 9–16 years postpartum among Danish women with a history of GDM. The association was particularly pronounced among women who only had one lifetime pregnancy.

KW - Adult

KW - Antibodies/blood

KW - Biomarkers

KW - Cohort Studies

KW - Diabetes, Gestational

KW - Female

KW - Humans

KW - Hyperthyroidism

KW - Hypothyroidism/blood

KW - Iodide Peroxidase/immunology

KW - Lactation/physiology

KW - Pregnancy

KW - Risk Factors

KW - Thyroid Gland/physiology

KW - Thyroxine/blood

KW - Time Factors

KW - Women's Health

U2 - 10.3390/nu10070938

DO - 10.3390/nu10070938

M3 - Journal article

C2 - 30037073

SN - 2072-6643

VL - 10

JO - Nutrients

JF - Nutrients

IS - 7

M1 - 938

ER -