Long-Term Follow-Up of Women with Postpartum Thyroiditis

RESEARCH HIGHLIGHTS www.nature.com/clinicalpractice/endmet

procedure in patients with Graves’ disease and Beneficial effects of cereal fiber active endocrine ophthalmopathy because of on glucose metabolism the low risk of surgical complications. Marie Lofthouse Insulin secretion after eating is stimulated by Original article Järhult J et al. (2005) Graves’ disease with increased blood glucose and secretion of glu- moderate–severe endocrine ophthalmopathy—long term cose-dependent insulinotropic polypeptide results of a prospective, randomized study of total or subtotal (GIP) and glucagon-like peptide 1 (GLP-1). thyroid resection. Thyroid 15: 1157–1164 Insoluble fiber is associated with a reduced risk of type 2 diabetes, but interpretation of the effects of whole grains on glucose metabolism Long-term follow-up of women can be difficult, because of the presence of with postpartum thyroiditis other potentially active ingredients, such as protein, antioxidants and phytoestrogens. There is a lack of consensus over if, and when, Researchers in Germany have studied the pregnant women should be routinely screened effect of purified insoluble cereal fibers on for subclinical thyroid disease. Postpartum glucose, insulin, GIP and GLP-1 in 14 healthy thyroid itis is a common condition that occurs women with normal glucose tolerance. On six during the first year after delivery and is to eight occasions, subjects consumed three character ized by transient thyrotoxicosis, with matched portions of bread enriched with wheat or without hypothyroidism. A high proportion fiber, oat fiber, resistant starch, or control of affected women develop persistent hypo- bread, and the next day consumed three por- thyroidism (PH), which negatively influences tions of control bread. The insulin response on the outcome of future pregnancies. day 1 was earlier for both wheat and oats than Lucas et al. collected long-term follow up for control. GIP response was also earlier after data for 42 women (aged 19–40 years) with oat-fiber consumption, but GLP-1 was not postpartum thyroiditis, who were followed up affected by any fiber. Those who consumed every 3 months during the first postpartum fiber-enriched bread on day 1 had a reduced year, then once or twice annually thereafter glucose response after consumption of control (mean 8.2 ± 2.2 years). During follow-up, 10 bread on day 2. Fiber enrichment had no effect women had a subsequent pregnancy, and on insulin, GIP or GLP-1 levels on day 2. in 5 of these women postpartum thyroiditis The authors suggest that improved glucose recurred. Over the study period, 14 women handling might result from increased insulin developed PH; 4 cases were in women who sensitivity or non-insulin-dependent glucose had a subsequent pregnancy. PH occurred uptake. They conclude that diet enrichment only in women whose postpartum thyroiditis with insoluble cereal fiber offers a means to episode included hypothyroidism. The risk of improve carbohydrate metabolism, but that the developing PH was higher if the baby was a findings need to be confirmed in larger studies girl (P <0.05), and increased with increasing that include diabetic patients. More work is TSH concentration during the episode of also needed to discover the mechanisms postpartum thyroiditis (P = 0.004). underlying the effects seen in the study. The sixth month postpartum is the ideal time Jim Casey to diagnose postpartum thyroiditis and to iden- Original article Weickert MO et al. (2005) Impact of tify women at risk of developing PH, say the cereal fibre on glucose-regulating factors. Diabetologia 48: authors. In their study, 37 women had hor- 2343–2353 mone abnormalities at the sixth-month postpartum check, including all those who later developed PH (all 14 of these had TSH levels Obesity-related insulin >6 mIU). Screening would enable levothyroxine resistance is reversible after treatment to be initiated in those at risk, so that weight loss levels of TSH could be normalized before any subsequent pregnancies. Obesity is characterized by an increase in the Caroline Barranco number (hyperplasia) and size (hypertrophy) of Original article Lucas A et al. (2005) Postpartum thyroiditis: adipocytes, and by insulin and catecholamine long-term follow-up. Thyroid 15: 1177–1181 resistance. The basal rate of lipolysis is higher

64 NATURE CLINICAL PRACTICE ENDOCRINOLOGY & METABOLISM FEBRUARY 2006 VOL 2 NO 2