Correlation between earthworms and plant litter decomposition in a tropical wet forest of Puerto Rico

Earthworms are recognized to play an important role in the decomposition of organic materials. To test the use of earthworms as an indicator of plant litter decomposition, we examined the abundance and biomass of earthworms in relation to plant litter decomposition in a tropical wet forest of Puerto Rico. We collected earthworms at 0–0.1 m and 0.1–0.25 m soil depths from upland and riparian sites that represent the natural variation in soils and decomposition rates within the forest. Earthworms were hand-sorted and weighed for both fresh and dry biomass. Earthworms were dominated by the exotic endogeic species Pontoscolex corethrurus Müller; they were more abundant, and had higher biomasses in the upland than in riparian sites of the forest. Plant leaf litter decomposed faster in the upland than riparian sites. We found that earthworm abundance in the upper 0.1 m of the soil profile positively correlated with decomposition rate of plant leaf litter. Ground litter removal had no effect on the abundance or biomass of endogeic earthworms. Our data suggest that earthworms can be used to predict decomposition rates of plant litter in the tropical wet forest, and that the decomposition of aboveground plant litter has little influence on the abundance and biomass of endogeic earthworms.     

Highly methoxylated pectin improves insulin resistance and other cardiometabolic risk factors in Zucker fatty rats

In this study, we evaluated the effect of a highly methoxylated apple pectin (HMAP) on cardiometabolic risk factors in Zucker fatty rats. beta-Glucan, a fiber known for its hypocholesterolemic properties, also was used. The rats fed both fiber-enriched diets exhibited a reduction in body weight and in total cholesterol and triglycerides when compared to the Zucker fatty rats fed the standard diet. The effect on the lipid profile was more remarkable in the HMAP group. A decrease in blood glucose was only noticed in this group. Moreover, a decrease in plasma insulin, HOMA-IR, and HOMA-beta was noticed in the fiber groups, and in particular in the HMAP group, these variables being similar to the lean rats. Blood pressure and endothelial function were similar in all the Zucker fatty rats. These results warrant evaluation in humans to determine if HMAP could be used as a functional ingredient to reduce lipid profile, insulin resistance, and other cardiometabolic risk factors.     

Protozoa from aboveground and ground soils of a tropical rain forest in Puerto Rico

Decomposition occurs in the aboveground and ground litter and soils of tropical rain forests, but little is known about the protozoa that stimulate bacterial activity and turnover. I examined litter and ground soils, epiphytic bryophyte soils on tree trunks and branches, and adventitious roots of lianas attached to tree trunks, within 2 m above ground in the Luquillo Experimental Forest, within the Caribbean National Forest, Puerto Rico. Amoebae numbered 69,000–170,000, ciliates 1000–25,000, and testate amoebae 58,000–190,000 g⁻¹ dry wt. of litter, but were reduced by 0.25–0.5 of these abundances in the underlying soils. In the aboveground soils, amoebae numbered 64,000–145,000, ciliates 1000–8000, and testate amoebae 84,000–367,000 g⁻¹ dry wt. of soil. Eighty species of ciliates and 104 species of testate amoebae were found. About 50% of the individuals in ciliate and 33% in testate amoebae populations were small r-selected species, illustrating that functional differences between species determine community composition. Although protozoan numbers are best described as “protozoan potential” because many individuals may be dormant, the high moisture content of tropical rain forest litter and soils suggest almost continually connected soil water films (necessary for protozoan transport), and together with the large numbers and biodiversity of protozoa, suggest that a major proportion of these protozoa contribute to the bacterial decomposition channel of organic matter.     

Dietary diversity score and cardiovascular risk factors in Tehranian adults

AIM: To evaluate the relationship between dietary diversity score (DDS) and cardiovascular risk factors in Tehranian adults. METHODS: In this population-based cross-sectional study, a representative sample of 581 subjects (295 males and 286 females) aged over 18 years, residents of Tehran, participated. Hypercholesterolaemia, hypertriglyceridaemia and low high-density lipoprotein cholesterol were defined according to the Adult Treatment Panel III guidelines of the National Cholesterol Education Program. Diabetes was defined as fasting plasma glucose concentration > or = 126 mg dl(-1) or 2-h post challenge glucose concentration > or = 200 mg dl(-1). Hypertension was defined on the basis of the sixth report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Dietary diversity was defined according to the Diet Quality Index revised. RESULTS: Mean (+/- standard deviation) DDS was 6.15 +/- 1.02. The probability of having diabetes (odds ratio (OR) among quartiles: 1.45, 1.26, 1.11 and 1.00, respectively; P for trend = 0.04) and hypertriglyceridaemia (OR = 1.41, 1.23, 1.05 and 1.00, respectively; P for trend=0.04) decreased with increasing quartile of the diversity score for whole grains. The probability of having obesity (OR among quartiles: 1.39, 1.06, 1.03 and 1.00, respectively; P for trend = 0.03), hypercholesterolaemia (OR = 1.46, 1.28, 1.11 and 1.00, respectively; P for trend = 0.03), hypertension (OR = 1.32, 1.17, 1.13 and 1.00, respectively; P for trend = 0.03) and high low-density lipoprotein cholesterol (LDL-C) (OR = 1.25, 1.12, 1.07 and 1.00, respectively; P for trend = 0.04) decreased with increasing quartile of the diversity score for vegetables. The probability of having hypercholesterolaemia, high LDL-C, hypertension and diabetes decreased with quartile of the DDS. But the probability of being obese increased with quartile of the DDS (P for trend = 0.03). CONCLUSION: DDS was inversely associated with cardiovascular risk factors in this cross-sectional study. Increased diversity scores of diets, to increase the variety score for vegetables, may be emphasised in programmes attempting to bring about changes in lifestyle.     

Risk factors for iron-deficiency anaemia among pregnant women living in rural Vietnam

OBJECTIVE: To assess the prevalence of anaemia in rural Vietnam and to determine its risk factors. DESIGN: A cross-sectional survey. SETTING: Vietnam, Nghe An Province. STUDY POPULATION: The total number of participants was 439. Of these participants, one was excluded from the study due to a mental disorder. Forty-seven did not participate in the test for parasites and 68 did not complete at least one of the questions. RESULTS: The prevalence of anaemia (haemoglobin (Hb) <11.0 g dl(-1)) was 43.2% and of severe anaemia (Hb <8.0 g dl(-1)) was 0.5%. Taking iron tablets, the consumption of eggs and the preference for Western medicine significantly and positively correlated with Hb concentration in the pregnant women in a multiple regression analysis. Pregnancy duration and hookworm infestation significantly and negatively correlated with Hb concentration in the pregnant women. CONCLUSION: The prevalence of anaemia in rural Vietnam has remained as high as that found in the national anaemia survey in 2000. The results of the present study could aid in the development of an iron-deficiency anaemia programme among pregnant women in rural Vietnam that emphasises iron supplementation, parasite control and improved diet, including the consumption of eggs. The programme's focus should be on women who prefer traditional medicine to Western medicine.     

Methane and nitrous oxide fluxes in an acid Oxisol in western Puerto Rico: effects of tillage, liming and fertilization

Changes in land use and management of tropical systems are considered to be major factors in the recent upsurge in increases in atmospheric nitrous oxide (N₂O) and methane (CH₄). Studies were initiated in western Puerto Rico grasslands to determine the effect of plowing, or liming and fertilizing an acid Oxisol on the soil–atmosphere exchanges of N₂O and CH₄. Weekly field flux measurements and field manipulation and laboratory studies were conducted over 22 months during 1993–1995. We found that N₂O emissions from an Oxisol acidified to pH 4 were generally lower than from pH 6 Oxisol soils that were used as reference controls. Plowing the grasslands did not change mean N₂O emission rates from either pH soil. Liming the acidified Oxisol to pH 6 tended to increase N₂O emissions to the rates from the undisturbed grassland. Fertilizing the acidified grassland increased N₂O emissions but much less than when these soils were both limed and fertilized. Short-term field studies employing nitrification inhibitors in which we measured nitric oxide (NO) and N₂O emissions, demonstrated that nitrification rates generally control N₂O emissions; thus these were lower in unlimed soil. It is likely that NO was produced through the chemical decomposition of nitrite, which in turn, was a product of biological nitrification. Soil consumption of atmospheric CH₄ in the acidified Oxisol was about one-fourth of that in the pH 6 reference soil. Liming did not restore CH₄ consumption in the acid soil to rates comparable to those in the reference Oxisol. We conducted a laboratory induction study to determine if incubation of these limed or unlimed acidified soils with high concentrations of CH₄ could induce methanotrophic activity. Comparable uptake rates to the control soils were not induced by these incubations. These studies illustrate that management of soil can considerably affect the soil–atmosphere exchange of such trace gases as N₂O and CH₄ which can affect global atmospheric properties.     

Obesity and related risk factors among low socio-economic status minority students in Chicago

OBJECTIVES: To assess overweight and related risk factors among urban low socio-economic status (SES) African-American adolescents in an attempt to study the underlying causes of ethnicity and gender disparities in overweight. METHODS: Cross-sectional data collected on anthropometric measures, diet, physical activity and family characteristics from 498 students in grades 5-7 in four Chicago public schools were analysed to study the risk factors for overweight using stepwise regression analysis. RESULTS: Only 37.2% of the students lived with two parents. Nearly 90% had a television (TV) in their bedroom, and had cable TV and a video game system at home. Overall. 21.8% (17.7% boys versus 25.1% girls) were overweight (body mass index (BMI) >/= 95th percentile); and 39.8% had a BMI >/= 85th percentile. Compared with national recommendations, they had inadequate physical activity and less than desirable eating patterns. Only 66.1% reported having at least 20 min vigorous exercise or 30 min of light exercise in >/= 5 days over the past 7 days; 62.1% spent >3 h days- 1 watching TV/playing video games/computer, while 33.1% spent >/= 5 h days- 1. Their vegetable and fruit consumption was low, and they consumed too many fried foods and soft drinks: 55.1% consumed fried food twice or more daily and 19.5% four times or more daily; 70.3% consumed soft drinks twice or more daily and 22.0% four times or more daily on average. Gender, physical activity and pocket money were significant predictors of overweight (P < 0.05). CONCLUSIONS: Several factors in the students' behaviours, school and family environments may increase overweight risk among this population. There is a great need for health promotion programmes with a focus on healthy weight and lifestyle, and targeting urban low-SES minority communities.     

Interactive effects of native and exotic earthworms on resource use and nutrient mineralization in a tropical wet forest soil of Puerto Rico

Investigation of single or mixed assemblages of native Estherella sp. and exotic Pontoscolex corethrurus from a rain forest in Puerto Rico was undertaken to understand resource use patterns, and linkages with C and N mineralization in a 19-day incubation. Resource use was explored with addition of ¹⁵N-enriched leaf litter and ¹³C-enriched glucose to reconstructed organic and mineral soil horizons. Juvenile Estherella sp. became at least 6.06‰ more enriched in ¹³C than sub-adult Estherella sp. or adult P. corethrurus. Sub-adult Estherella sp. became >3.6‰ enriched in ¹³C over P. corethrurus. '¹⁵N acquired by P. corethrurus was greater by 0.83-1.56‰ in the mixed-species than the single-species assemblages. '¹⁵N of sub-adult Estherella sp. was enriched by 0.73-0.81‰ over juvenile Estherella sp. in the single-species assemblage. Net N immobilization occurred in the organic layer of all ¹⁵N-enriched treatments. Net N mineralization in mineral soil layers was significantly greater in microcosms with P. corethrurus than in those containing only Estherella sp.. Cumulative respiration was greatest in P. corethrurus assemblages, however, assemblages with only Estherella sp. released more ¹³C in respiration. P. corethrurus assimilated different N resources when incubated with, as compared to without, native Estherella sp.. '¹³C and '¹⁵N signatures acquired by assimilation of ¹³C and ¹⁵N differed by species, developmental stage, and competitive interactions. The results showed that alone, exotic P. corethrurus induced higher mineralization rates than native Estherella sp., but that the interaction of exotic and native species impinged on resource use by P. corethrurus, reducing the effect of the exotic species on C and N mineralization. Invasion of exotic P. corethrurus may change the mineralization potentials of C and N and their biogeochemical cycling in soils.     

Leisure-time and occupational physical activity in relation to cardiovascular risk factors and eating habits in French adults

OBJECTIVE: To investigate the relationships of two main physical activity domains (during leisure and at work) with cardiovascular risk factors and eating habits. DESIGN: Cross-sectional study. SETTING: Preventive medicine centre. SUBJECTS: In 5478 adults (32% women, aged 20-80 years) who consecutively underwent a standardised health examination, leisure-time physical activity (LTPA; i.e. non-sport leisure and sport activities), occupational physical activity (OPA) and eating habits were assessed by self-administered questionnaires. We analysed sex-specific relationships of LTPA and OPA (in quartiles) with (1) various cardiovascular risk factors and (2) eating habits using analysis of variance and logistic regression, respectively. RESULTS: In both genders, with and without adjustment for education in addition to age, LTPA was associated negatively with body mass index, body fat, waist circumference, resting heart rate, diastolic blood pressure and triglycerides, and positively associated with high-density lipoprotein cholesterol (all P < or = 0.005). OPA adjusted for age only was positively associated with most cardiovascular risk factors but these associations were not significant after further adjustment on education (except for waist circumference in women). Age- and education-adjusted LTPA was associated with increased frequency of consumption of fruits (odds ratio (OR) = 2.05, 95% confidence interval (CI) 1.68-2.52 in men; OR = 1.90, 95% CI 1.41-2.05 in women) and vegetables (OR = 1.81, 95% CI 1.48-2.21 in men; OR = 2.22, 95% CI 1.66-2.97 in women). CONCLUSIONS: The data emphasise the favourable associations of LTPA, a modifiable behaviour, with various cardiovascular risk factors and healthy eating habits. The results also suggest that the relationships of OPA with cardiovascular risk factors depend, at least in part, on socio-economic status as reflected by educational level.     

Diagnosed skin diseases among migrant farmworkers in North Carolina: prevalence and risk factors

Skin diseases are common among farmworkers, yet little research documents their prevalence and risk factors. This analysis documents the prevalence of skin diseases among farmworkers in North Carolina, examines variation in the prevalence across the agricultural season, and delineates factors associated with skin disease. Data are from a longitudinal surveillance study with assessments at approximately three-week intervals from May through October 2005. The sample included 304 farmworkers from 45 camps with 1048 data points. Data collection included a structured interview and a standard set often digital photographs. A board-certified dermatologist reviewed the photographs and made specific diagnoses in five categories: inflammatory disease, infection, pigmentary disorder, tumor, and trauma. The prevalences of the five skin disease categories and specific diagnoses are described with counts and frequencies for the entire season and for six time periods. The inflammatory disease and infectious disease categories are modeled with an extension of logistic regression that accounts for repeated measures and clustering of farmworkers within camps. Farmworkers experience high levels of inflammatory skin disease (57.2%) including acne, folliculitis, and contact dermatitis; infectious skin disease (73.8%) including tinea pedis, onychomycosis, and warts; pigmentary disorders (19.1%); and trauma (34.5%). The odds of inflammatory skin disease decreased with age, while those for infectious skin disease increased with age. The odds of inflammatory skin disease increased with pesticide exposure and decreasing housing quality. Skin diseases are highly prevalent among farmworkers. Research is needed to delineate specific factors causing high levels of infection and inflammation in this population.     

Detection of cardio-metabolic risk by BMI and waist circumference among a population of Guatemalan adults

BACKGROUND: BMI and waist circumference (WC) are used to screen for cardio-metabolic risk; however it is unclear how well these indices perform in populations subject to childhood stunting. OBJECTIVES: To evaluate BMI and WC as indicators of cardio-metabolic risk and to determine optimal cut-off points among 1325 Guatemalan adults (44 % stunted: 162 cm men). METHODS: Cardio-metabolic risk factors were systolic/diastolic blood pressure 85 mmHg, glucose 5 mmol/l, TAG 7 mmol/l, ratio of total cholesterol to HDL-cholesterol 0, and the presence of two or more and three or more of the preceding risk factors. Receiver operating characteristic (ROC) curve analysis was used. RESULTS: Areas under the ROC curve were in the range of 005978 for WC among men and 006472 among women, respectively. Optimal cut-off points for BMI were 242651 kg/m2 stunted; 242656 kg/m2 among women (262769 kg/m2 non-stunted). Optimal cut-off points for WC were 879134 cm stunted; 889333 cm among women (909486 cm non-stunted).ConclusionOptimal cut-off points for BMI were slightly higher among women than men with no meaningful differences by stature. Optimal cut-off points for WC were several centimetres lower for stunted compared with non-stunted men, and both were substantially lower than the current recommendations among Western populations. Cut-off points derived from Western populations may not be appropriate for developing countries with a high prevalence of stunting.     

Prevalence and associated risk factors of undiagnosed diabetes among adult Moroccan Sahraoui women

OBJECTIVE: The goal of the present work was to examine the prevalence and associated risk factors of undiagnosed diabetes among urban Moroccan Sahraoui women. DESIGN AND SETTING: Randomised sample of adult women living in the city of Laayoune in south Morocco who visited public health centres during an immunisation campaign. Body weight, height, waist and hip circumferences, blood pressure, fasting plasma glucose (FPG), triglycerides, dietary intake and physical activity were collected. SUBJECTS: Data were obtained on 249 urban women aged 15 years and older, who were not pregnant. Only subjects identified as of Sahraoui origin were eligible for this investigation. RESULTS: The prevalence of impaired fasting glucose (IFG) was 5.5% and that of undiagnosed diabetes 6.4%. Diabetes and IFG were more common among older and obese women as well as among women with hypertension or a family history of diabetes. In addition, sucrose intakes were higher in women with diabetes than in those with normal FPG. Also, physical activity estimated as the time spent in walking was negatively associated with FPG. Regression analyses showed an independent association of age, obesity, family history of diabetes and triglycerides with diabetes. CONCLUSION: The high proportion of unknown diabetes suggests the need for increased diabetes awareness in this population. The data suggest also the involvement of obesity in diabetes and the potential importance of intervention strategies to reduce population adiposity for the prevention and management of cardiovascular risk factors.