Long-term effects of nutrient intervention on markers of bone remodeling and calciotropic hormones in late-postmenopausal women

BACKGROUND: Adequate intakes of calcium and vitamin D reduce bone loss and fracture risk in the elderly. Other nutrients also affect bone health, and adequate intakes may influence bone turnover and balance. OBJECTIVE: We compared the long-term effects on bone turnover markers and calciotropic hormones of a multinutrient supplement, a calcium and vitamin D supplement, and dietary instruction aimed at increasing calcium intake through foods. DESIGN: Ninety-nine healthy postmenopausal women participated in a 3-y, randomized trial, receiving either 1) supplemental calcium (1450 mg/d) and vitamin D [10 microg (400 IU)/d], 2) calcium, vitamin D, and other nutrients (multinutrient supplement), or 3) dietary instruction (dietary control group). Data are from 83 subjects who completed the trial. RESULTS: Increases over baseline in calcium intakes and serum 25-hydroxyvitamin D concentrations were sustained over 3 y in all treatment groups. Circulating parathyroid hormone concentrations were reduced at year 1 in all treatment groups but trended toward baseline thereafter. Bone turnover markers followed a similar pattern, and none of the changes in biochemical concentrations differed significantly between groups. CONCLUSIONS: All 3 interventions offer long-term feasibility for increasing calcium intake and serum 25-hydroxyvitamin D concentrations. The dietary addition of micronutrients implicated in skeletal physiology confers no obvious bone-sparing effect in healthy postmenopausal women beyond that of calcium and vitamin D alone. The attenuation over time in suppression of parathyroid hormone and bone turnover might help explain why nutrient intervention tends to have less of a bone-sparing effect than do skeletally active medications such as estrogen or bisphosphonates.     

Birthweight and caffeine consumption

OBJECTIVES: To assess the association between maternal caffeine consumption during pregnancy and low birth weight, prematurity and intrauterine growth retardation. METHODS: A case-control was carried out and 354 newborns of single labor with birthweight <2,500 g (cases) and 354 with birthweight >3,000 g (controls) were analyzed. Caffeine consumption was calculated based on daily consumption of coffee, soft drinks and tea. Results were adjusted using multiple logistic regression for the following confounders: mother's age, schooling, income, marital status, skin color, parity, smoking, previous low birthweight children, mother's pre-pregnancy weight, employment status, interval between pregnancies, prenatal care and high blood pressure. RESULTS: For caffeine consumption <300 mg/day and >300 mg/day, the adjusted odds ratios for low birthweight were: 0.72 (95%IC=0.45-1.25) and 0.47 (95%IC=0.24-0.92); prematurity: 0.59 (95%IC=0.32-1.09) and 0.32 (95%IC=0.15-0.72); and intrauterine growth retardation: 1.16 (95%IC=0.45-3.01) and 0.64 (95%IC=0.20-1.98), respectively. CONCLUSION: There was no association between caffeine consumption during pregnancy and low birthweight, prematurity and intrauterine growth retardation.     

The spread and effect of HIV-1 infection in sub-Saharan Africa

Africa is the continent most severely affected by the global HIV-1 epidemic, with east and southern Africa in general more severely affected than west and central Africa. Differences in the spread of the epidemic can be accounted for by a complex interplay of sexual behaviour and biological factors that affect the probability of HIV-1 transmission per sex act. Sexual behaviour patterns are determined by cultural and socioeconomic contexts. In sub-Saharan Africa, some traditions and socioeconomic developments have contributed to the extensive spread of HIV-1 infection, including the subordinate position of women, impoverishment and decline of social services, rapid urbanisation and modernisation, and wars and conflicts. Populations in many parts of Africa are becoming trapped in a vicious circle as the HIV-1 epidemic leads to high mortality rates in young and economically productive age groups, and thus leads to further impoverishment. Interventions to control HIV-1 should not only target individuals, but also aim to change those aspects of cultural and socioeconomic context that increase the vulnerability to HIV-1 of people and communities.     

Neuroendocrine tumors of the pancreas in von Hippel-Lindau disease: spectrum of appearances at CT and MR imaging with histopathologic comparison

PURPOSE: To demonstrate the imaging characteristics of neuroendocrine tumors (NETs) of the pancreas in patients with von Hippel-Lindau (VHL) disease to establish diagnostic criteria. MATERIALS AND METHODS: Twenty-five patients with VHL disease and 29 surgically confirmed pancreatic NETs were included. Screening computed tomographic (CT) and/or magnetic resonance (MR) imaging findings were reviewed, and tumor number, diameter, growth rates (doubling time), location, presence of metastatic disease, and attenuation or enhancement properties were determined. RESULTS: Eighteen of 29 (62%) pancreatic NETs were smaller than 3.0 cm in diameter and enhanced homogeneously on contrast material-enhanced CT and MR images. No tumor smaller than 3.0 cm metastasized. Tumors 3.0 cm or larger (11 [38%] of 29) more often enhanced heterogeneously, and two of 11 were associated with hepatic metastases. Smaller (<3.0 cm) tumors displayed longer mean doubling times (mean, 927 vs 351 days) than did larger (> or =3.0 cm) tumors; however, there was considerable overlap. Fifteen (52%) tumors were located in the pancreatic head; eight (28%), in the tail; and six (21%), in the body. Ten (40%) patients with pancreatic NETs had associated pheochromocytomas, and 22 (88%) had no or mild pancreatic cystic disease, which is substantially more than the general population of patients with VHL disease. CONCLUSION: Pancreatic NETs in VHL have characteristic features at CT and MR imaging: Most are small, located in the pancreatic head, and enhance homogeneously. Tumors larger than 3.0 cm are prone to metastasize and enhance heterogeneously.     

Antioxidant supplementation decreases lipid peroxidation biomarker F(2)-isoprostanes in plasma of smokers.

Free radicals in cigarette smoke (CS) cause oxidative damage to proteins, DNA, and lipids, contributing to the pathobiology of atherosclerosis, heart disease, and cancer. In vitro studies have shown that antioxidants quench free radicals and ameliorate certain aspects of biomolecular damage caused by CS. It is hypothesized that a combination of antioxidants is more effective than a single antioxidant, due to their interactions. To investigate whether supplemental antioxidants reduce CS-related lipid peroxidation in vivo and whether they are more effective in combination, we conducted an intervention study in smokers. In a randomized double-blind placebo-controlled trial, we investigated whether vitamin C or an antioxidant mixture containing vitamin C, alpha-lipoic acid, and vitamin E decreases plasma F(2)-isoprostane levels, an index of oxidant stress, in smokers. Plasma of 126 smokers (mean age, 46 years; age range, 20-78 years) was analyzed for F(2)-isoprostanes at baseline and after intervention with antioxidants and placebo. In smokers with a body mass index (BMI) above the median, 2 months of daily supplementation with 500 mg of vitamin C decreased plasma F(2)-isoprostane levels by 28.8 pmol/liter when compared with the placebo group (P = 0.001); levels in the mixture group were 7.45 pmol/liter lower after treatment, but this difference was not statistically significant (P = 0.14). There was no treatment effect in smokers with a low BMI. BMI was significantly positively associated with plasma F(2)-isoprostane levels (trend P = 0.001). Antioxidants decrease smoking-related lipid peroxidation markers of oxidative stress in humans with high BMI. Our results do not indicate that an antioxidant combination is more effective than vitamin C alone. The intake of antioxidants may help prevent smoking-related diseases. Smoking cessation should still be considered the most effective way to prevent smoking-related diseases.     

A review: dietary and endogenously formed <Emphasis Type="Italic">N-</Emphasis>nitroso compounds and risk of childhood brain tumors

Maternal dietary exposure to N-nitroso compounds (NOC) or to their precursors during pregnancy has been associated with risk of childhood brain tumors. Cured meat is one source of exposure to dietary NOC and their precursors. Most epidemiological studies that have examined the role of maternal consumption of cured meats during pregnancy have found a significant positive association between maternal intake of cured meat and the risk of childhood brain tumor (CBT). NOC consist of two main groups, N-nitrosamines and N-nitrosamides. The carcinogenicity profiles of NOC suggest that N-nitrosamides rather than N-nitrosamines are the compounds that may be associated with CBT and that they should be investigated more closely in epidemiological studies. We present a review of the chemical and carcinogenic properties of NOC in connection with the findings of case–control studies. This approach may be helpful in determining the essential information that must be collected in future epidemiological studies on CBT.     

Incidence of leukemias in children from El Salvador and Mexico City between 1996 and 2000: Population-based data

Background

There are very few studies that report the incidence of acute leukemias in children in Latin America. This work assesses the incidence of acute leukemias, between 1996 and 2000, in children from 0–14 years old who were attended at the Mexican Social Security Institute in Mexico City and in children from 0–11 years old in El Salvador.

Methods

Design: Population-based data. Hospitals: In San Salvador, El Salvador, Hospital Nacional de Niños "Benjamín Bloom", the only center in El Salvador which attends all children, younger than 12 years, with oncologic disease. The Pediatric Hospital and the General Hospital of the Mexican Social Security Institute in Mexico City, the only centers in Mexico City which attend all those children with acute leukemia who have a right to this service. Diagnosis: All patients were diagnosed by bone marrow smear and were divided into acute lymphoid leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML), and unspecified leukemias (UL). The annual incidence rate (AIR) and average annual incidence rate (AAIR) were calculated per million children. Cases were stratified by age and assigned to one of four age strata: 1) <1 year; 2) 1–4 years; 3) 5–9 years, or 4) 10–14 or 10–11 years, for Mexico City and El Salvador, respectively.

Results

The number of cases was 375 and 238 in El Salvador and Mexico City, respectively. AAIRs in Mexico City were 44.9, 10.6, 2.5, 0.5, and 58.4 per million children for ALL, AML, CML, UL, and total leukemias, respectively. The AAIRs in El Salvador could not be calculated because the fourth age stratum in El Salvador included children only from 0–11 years old. The incidence rates for the Salvadoran group of 0–11 year olds were 34.2, 7.1, 0.6, 0.2, and 43.2 per million children for ALL, AML, CML, UL, and total leukemias, respectively.

Conclusion

Reported AIRs for each age group in El Salvador were similar to those from other American countries. The AAIR of ALL in Mexico City is one of the highest reported for North America.