Association between prolonged breastfeeding and bone mineral density and osteoporosis in postmenopausal women: KNHANES 2010-2011

This study showed that a negative correlation between duration of breastfeeding and bone mineral density (BMD) in the lumbar spine and prolonged breastfeeding is an independent risk for osteoporosis in postmenopausal women. The present study suggests that postmenopausal women with a history of prolonged breastfeeding require more careful screening for osteoporosis.

INTRODUCTION

Several studies suggest that breastfeeding and childbirth lead to maternal calcium loss and a decline in BMD. While the association between breastfeeding and BMD immediately after weaning is well-established, the effects of breastfeeding on postmenopausal women have been controversial. The aim of this study was to examine the effects of breastfeeding on bone mineral density (BMD) and the prevalence of osteoporosis in postmenopausal women.

METHODS

The present study was a cross-sectional survey based on the Korea National Health and Nutrition Examination Survey (KNHANES) 2010 and 2011 data. The association between breastfeeding and BMD and osteoporosis was examined in 1222 postmenopausal women.

RESULTS

The duration of breastfeeding and BMD in the lumbar spine showed a negative correlation. The association between duration of breastfeeding and BMD remained significant after adjustment for reproductive factors and other confounding factors (P = 0.008). However, the number of deliveries and age at the time of delivery did not correlate with BMD at any site after adjustment. Moreover, the prevalence of osteoporosis in postmenopausal women with a history of prolonged breastfeeding was significantly higher than that in women with a short history of breastfeeding (≥37 months, OR = 3.292; 95 % CI 1.485-7.299). The prevalence of lumbar spine fracture showed a significant increasing trend with the increase in the duration of breastfeeding.

CONCLUSION

Prolonged breastfeeding was significantly associated with low BMD in the lumbar spine and higher prevalence of osteoporosis. However, the number of deliveries or age at the time of childbirth did not influence BMD.

BaTiO3 doped Na0.5K0.5NbO3 thin films deposited by using eclipse shutter enhanced pulsed laser deposition method

We have investigated structural, electrical, and electro-mechanical properties of lead-free piezoelectric BaTiO3 doped Na0.5K0.5NbO3 (BTO-NKN) thin films deposited by pulsed laser deposition (PLD) methods. BTO-NKN thin films have been deposited on La0.5Sr0.5CoO3 (LSCO) bottom electrodes with LaAlO3 (LAO) substrates. X-ray diffraction data have shown that all the BTO-NKN and bottom electrodes are highly oriented with their c-axes normal to the substrates. In order to improve the morphology of BTO-NKN thin films, we have located an eclipse shutter between a target and a substrate. Root-mean-square roughness was changed from 91 nm to 21 nm with eclipse shutter enhanced PLD (E-PLD) method. Furthermore, the enhanced surface morphology leads to the improvement in electrical or electro-mechanical properties mainly due to increased density. Typical capacitance and d33 values of a BTO-NKN film deposited by E-PLD method are 1000 pF and 30 pmN, respectively.

Anti-T antibodies and peanut-agglutinin-binding glycoproteins in sera of patients with gastric cancer

Agglutinating antibodies to neuraminidase-treated red blood cells (anti-T agglutinins) are known to be reduced in patients with gastric cancer. The antigenic determinant of anti-T agglutinin is known to have a disaccharide structure [Gal(beta1-3)GalNAc], the same specificity as peanut agglutinin (PNA). We examined sera of 27 patients with gastric cancer and 30 controls for anti-T agglutinins, anti-T antibodies and PNA-binding glycoproteins. Anti-T agglutinins were titrated by a microtiter hemagglutination method. Levels of anti-T antibodies were determined by enzyme immunoassay using synthetic glycoconjugate [Gal(beta1-3)GalNAc O-alpha-linked to human serum albumin] as an antigen. Levels of PNA-binding glycoproteins in sera were measured by sandwich enzyme-linked lectin assay using wheat germ agglutinin and peroxidase-conjugated PNA. Titers of anti-T agglutinins were significantly lower in patients with gastric cancer than in controls (P = 0.041). Levels of anti-T antibodies were not significantly different in patients with gastric cancer and controls; however, decreased levels of anti-T antibodies were more frequent in patients with gastric cancer than in controls (P = 0. 001). Levels of PNA-binding glycoproteins were significantly higher in sera of patients with gastric cancer than in controls (P = 0.001). The levels of anti-T antibodies inversely correlated with the levels of PNA-binding glycoproteins in sera of patients with gastric cancer (r = -0.44, P = 0.021). These results suggest that the decrease in anti-T antibodies in sera of patients with gastric cancer might be due to immune complex formation between circulating PNA-binding glycoproteins and anti-T antibodies.

Glomerular hyperfiltration in Koreans with non-insulin-dependent diabetes mellitus

Glomerular hyperfiltration (GHF) may play an important role in the pathogenesis of diabetic nephropathy. The prevalence of GHF in non-insulin-dependent diabetes mellitus (NIDDM) is reported to vary in different populations, ranging from 35% in black Americans with new-onset diabetes to less than 5% in whites. We measured glomerular filtration rate (GFR) by 51Cr-EDTA clearance methods in 284 Korean NIDDM patients without overt nephropathy. Glomerular hyperfiltration (defined as GFR > 140 mL/min/1.73 m2) was found in 25% (71 of 284) of the patients. Thirty percent and 15% of the patients with known duration of diabetes less than 5 years and more than 10 years, respectively, showed GHF. Microalbuminuria (defined as urinary albumin excretion rate 20 to 200 micrograms/min) was found in 23% (64 of 284) of the patients. The mean GFR of the microalbuminuric patients was not significantly different from that of the normoalbuminuric patients (121.5 +/- 30.1 mL/min/1.73 m2 v 124.9 +/- 26.4 mL/min/1.73 m2; P = NS). However, when the patients with microalbuminuria were divided according to the presence or absence of retinopathy, the microalbuminuric patients with retinopathy had a lower GFR compared with the microalbuminuric patients without retinopathy (109.6 +/- 35.5 mL/min/1.73 m2 v 130.0 +/- 26.3 mL/min/1.73 m2; P < 0.01). These results show that the prevalence of GHF in Korean NIDDM patients without overt nephropathy is higher than that reported in whites and that it is similar to that in black Americans. The high prevalence of GHF in Korean NIDDM patients may contribute to the relatively higher prevalence of clinical diabetic nephropathy in this population.