Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau.

This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1-12ngg(-1)), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09-0.12 and 0.12-0.14µgg(-1) (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg(-1) is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8-10ngg(-1) (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.

Diet or exercise, or both, for weight reduction in women after childbirth.

BACKGROUND: Weight retention after pregnancy may contribute to obesity. It is known that diet and exercise are recommended components of any weight loss programme in the general population. However, strategies to achieve healthy body weight among postpartum women have not been adequately evaluated. OBJECTIVES: The objectives of this review were to evaluate the effect of diet, exercise or both for weight reduction in women after childbirth, and to assess the impact of these interventions on maternal body composition, cardiorespiratory fitness, breastfeeding performance and other child and maternal outcomes. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2006) and LILACS. We scanned secondary references and contacted experts in the field. SELECTION CRITERIA: All published and unpublished randomised controlled trials (RCT) and quasi-randomised trials of diet or exercise or both, among women during the postpartum period. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed trial quality and extracted data. Results are presented using relative risk for categorical data and weighted mean difference (WMD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity. MAIN RESULTS: Six trials involving 245 women were included. Women who exercised did not lose significantly more weight than women in the usual care group (one trial; n = 33; WMD 0.00 kg; 95% confidence interval (CI) -8.63 to 8.63). Women who took part in a diet (one trial; n = 45; WMD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (four trials; n = 169; WMD -2.89 kg; 95% CI -4.83 to -0.95), lost significantly more weight than women in the usual care. There was no difference in the magnitude of weight loss between diet and diet plus exercise group (one trial; n = 43; WMD 0.30 kg; 95% CI -0.60 to 0.66). The interventions seemed not to affect breastfeeding performance adversely. AUTHORS' CONCLUSIONS: Preliminary evidence from this review suggests that dieting and exercise together appear to be more effective than diet alone at helping women to lose weight after childbirth, because the former improves maternal cardiorespiratory fitness level and preserves fat-free mass, while diet alone reduces fat-free mass. For women who are breastfeeding, more evidence is required to confirm whether diet or exercise, or both, is not detrimental for either mother or baby. Due to insufficient available data, additional research, with larger sample size, is needed to confirm the results.

Long-term weight loss after diet and exercise: a systematic review.

OBJECTIVE: To assess the effectiveness of dietary interventions and exercise in long-term weight loss in overweight and obese people. DESIGN: A systematic review with meta-analysis. SUBJECTS: Overweight and obese adults-18 years old or older with body mass index (calculated as weight divided by the square of height in meters)>25. DATA SOURCE: Medline, Cochrane Library and Lilacs databases up to March 2003. Also, published reviews and all relevant studies and their reference lists were reviewed in search for other pertinent publications. No language restrictions were imposed. STUDY SELECTION: Randomised clinical trials comparing diet and exercise interventions vs diet alone. All trials included a follow-up of 1 y after intervention. DATA EXTRACTION: Two reviewers independently abstracted data and evaluated the studies' quality with criteria adapted from the Jadad Scale and the Delphi list. DATA SYNTHESIS: The estimate of the intervention's effect size was based on the differences between the comparison groups, and then the overall effect was calculated. A chi-squared test was used to assess statistical heterogeneity. RESULTS: A total of 33 trials evaluating diet, exercise or diet and exercise were found. Only 6 studies directly comparing diet and exercise vs diet alone were included (3 additional studies reporting repeated observations were excluded). The active intervention period ranged between 10 and 52 weeks across studies. Diet associated with exercise produced a 20% greater initial weight loss. (13 kg vs 9.9 kg; z=1.86-p=0.063, 95%CI). The combined intervention also resulted in a 20% greater sustained weight loss after 1 y (6.7 kg vs 4.5 kg; z=1.89-p=0.058, 95%CI) than diet alone. In both groups, almost half of the initial weight loss was regained after 1 y. CONCLUSION: Diet associated with exercise results in significant and clinically meaningful initial weight loss. This is partially sustained after 1 y.