Inverse relationship between body mass index and mortality in older nursing home residents: a meta-analysis of 19,538 elderly subjects

Body mass index (BMI) and mortality in old adults from the general population have been related in a U-shaped or J-shaped curve. However, limited information is available for elderly nursing home populations, particularly about specific cause of death. A systematic PubMed/EMBASE/CINAHL/SCOPUS search until 31 May 2014 without language restrictions was conducted. As no published study reported mortality in standard BMI groups (<18.5, 18.5-24.9, 25-29.9, ≥30 kg/m(2)), the most adjusted hazard ratios (HRs) according to a pre-defined list of covariates were obtained from authors and pooled by random-effect model across each BMI category. Out of 342 hits, 20 studies including 19,538 older nursing home residents with 5,223 deaths during a median of 2 years of follow-up were meta-analysed. Compared with normal weight, all-cause mortality HRs were 1.41 (95% CI = 1.26-1.58) for underweight, 0.85 (95% CI = 0.73-0.99) for overweight and 0.74 (95% CI = 0.57-0.96) for obesity. Underweight was a risk factor for higher mortality caused by infections (HR = 1.65 [95% CI = 1.13-2.40]). RR results corroborated primary HR results, with additionally lower infection-related mortality in overweight and obese than in normal-weight individuals. Like in the general population, underweight is a risk factor for mortality in old nursing home residents. However, uniquely, not only overweight but also obesity is protective, which has relevant nutritional goal implications in this population/setting.

Usefulness of the Chinese Nutrition Screening (CNS) tool in predicting 12 month mortality in elderly Hong Kong Chinese living in institutions

OBJECTIVES

To determine the cut off score of the CNS in predicting 12 months mortality.

DESIGN

Data was collected and followed up from a previous study among elderly subjects (n = 515) living in community institutional setting. The risk of malnutrition and 12 months mortality was ranked by the CNS and compared with that by SGA. Reliability was assessed by the sensitivity and specificity of the prediction with SGA as well as BMI alone. Sensitivity and specificity was calculated to determine validity as well as using positive and negative predictive values in predicting mortality at 12 months.

RESULTS

All three tools (BMI, SGA, CNS) demonstrated significant difference of higher mortality rate (P < .001) in the malnourished group. CNS at score < or = 21 showed comparable results to SGA tool and BMI at classifying malnutrition. And using cut off score > or = 22 also show significant results with SGA in classifying patients with normal nutrition. CNS score at > or = 22 sensitivity was 60.9% and specificity was 72.9% with a Negative Predictive value of 92.3% and a Positive Predictive value of 25.8%.

CONCLUSION

CNS tool at cut off > or = 22 is just as good as using BMI or SGA in identifying those who have a normal nutritional status. This is useful in particular, when biochemical or anthropometric data is not available. This further validates the use of > or = 22 as the best cut off point with the CNS tool and just as good at predicting of mortality when compared with SGA and BMI assessments.

The acute and chronic toxicity of cadmium and zinc to two hydra species

The potential of two hydra species, Hydra vulgaris (pink) and Hydra viridissima (green), for use as invertebrate models for toxicity testing of waterborne metals was investigated. The acute and subchronic toxicities of cadmium (a nonessential metal) and zinc (an essential metal) were determined. Results showed that both the hydra species were more sensitive to cadmium than to zinc, and that green hydra were more sensitive than pink hydra. The mean (SE) 96 h LC50 values of cadmium and zinc for pink hydra were 83 (8.5) and 2300 (150) micrograms/L, respectively. For green hydra, the respective 96 h LC50 values for cadmium and zinc were 3.0 (0.0) and 935 (46.5) micrograms/L. The respective 7-day no-observed-effect-concentrations (NOEC) and lowest-observed-effect-concentrations (LOEC) for pink hydra were < 13 and 13 micrograms/L for cadmium, and < 250 and 250 micrograms/L for zinc. The respective 7-day NOEC and LOEC values for green hydra were 0.4 and 0.8, microgram/L for cadmium, and 38 and 75 micrograms/L for zinc. Neither 1, 2, or 3 x 90-min pulse-exposures to 0.4, 0.8, or 1.5 micrograms/L of cadmium had any significant deleterious effect on total green hydra numbers after seven days in clean water. Green hydra appeared to be excellent freshwater invertebrate models for testing dissolved metals based on their sensitivity and the ability to rapidly assess population reproduction in the laboratory.