Masahiro Umezaki

Variations in societal characteristics of spatial disease clusters: examples of colon, lung and breast cancer in Japan

BackgroundSpatial analyses and ecological studies are essential for epidemiology and public health. The present study combining these two methods was performed to identify spatial clusters of selected types of cancer in Japan and to determine their societal characteristics focusing on homogeneity among clusters.ResultsSpatial clusters of high mortality rates of male colon and lung cancer and of female breast cancer were identified by the spatial scan statistic using Japanese municipal data (N = 3360) from 1993 to 1998 and also municipalities were divided into four societal clusters based on socioeconomic indicators and population density (urban-rich, suburban, rural-poor, and clutter). Five, seven, and four mortality clusters were identified for lung, colon and breast cancer, respectively. For colon and breast cancer, most municipalities of all except one cluster were included in a single societal cluster (urban-rich). The municipalities associated with mortality clusters for lung cancer belonged to various societal clusters.ConclusionIncreased mortality rates of colon and breast cancer can be explained by homogenous societal characteristics related to urbanisation, although there were exceptional areas with higher mortality rates. The regional variation in lung cancer mortality rate appeared to be due to heterogeneous factors. These findings and the analysis performed in the present study will contribute to both nationwide and region-specific cancer prevention strategies.

Association of cord blood levels of lead, arsenic, and zinc with neurodevelopmental indicators in newborns: A birth cohort study in Chitwan Valley, Nepal

In this study, we aimed to investigate the association between in utero toxic (lead [Pb] and arsenic [As]) and essential element (zinc [Zn]) levels and neurodevelopmental indicators after birth in Chitwan Valley, Nepal. We conducted a hospital-based birth cohort study with 100 pregnant women in Chitwan, Nepal. We measured Pb, As, and Zn concentrations in cord blood. We assessed 100 infants at 1 day after birth, using the Brazelton neonatal behavioral assessment scale, third edition (NBAS III). Multivariate regression was performed to adjust for mothers age, parity, educational level, and body mass index (BMI); family income; and newborns birth weight, gestational age, and age in hours at the time of NBAS III assessment. Among the 7 clusters of NBAS III, the motor cluster score was inversely associated with the cord blood levels of Pb (coefficient=-2.15, at 95% confidence interval [CI]=-4.27 to -0.03). The cord blood levels of As were inversely associated with the state regulation cluster score (coefficient=-6.71, at 95% CI=-12.17 to -1.24). The cord blood levels of Zn were not associated with NBAS III scores. The cord blood levels of Pb and As, but not Zn, showed significant inverse association with the neurodevelopment of newborns. These results suggest that high levels of Pb or As exposure during the prenatal period may induce retardation during in utero neurodevelopment.

Mutual interaction between nutritional status and chronic arsenic toxicity due to groundwater contamination in an area of Terai, lowland Nepal

Objective: To reveal the inter-relationship between nutritional status and arsenic toxicity. Design: Cross-sectional study. Setting: A survey in an area of lowland Nepal, where a high prevalence of both skin manifestation and malnutrition was observed. Daily arsenic intake was estimated by measuring the arsenic concentration and daily consumption of the drinking water. Participants: Adult villagers (248 men and 291 women). About half were classified as “underweight” (body mass index <18.5), indicating poor nutritional status. Main results: Arsenic intake was negatively correlated with body mass index and substantially increased the prevalence of underweight individuals, among whom the prevalence of skin manifestations was 1.65-fold higher than normal weight individuals. When exposure level was considered, the prevalence of skin symptoms was consistently higher in the underweight than in the normal group. Although enhanced susceptibility in men was apparent by the increased prevalence of cutaneous symptoms, no sex difference was observed in the prevalence of underweight individuals related with exposure to arsenic. Conclusions: The present data suggested that exposure to arsenic is associated with an increased prevalence of underweight, a serious health problem in developing countries, which in turn is associated with increased skin manifestation of arsenic poisoning.

Influence of urbanisation on physical activity and dietary changes in Huli-speaking population: a comparative study of village dwellers and migrants in urban settlements.

The influence of urbanisation on physical activity and dietary changes was examined in a Papua New Guinea Highland population. Adult male and female subjects (n 56) were selected, including twenty-seven rural villagers and twenty-nine urban migrants. BMR was calculated from values measured in similar samples of Huli-speaking population, according to gender and body weight. Total daily energy expenditure (TEE) was assessed by 24 h heart rate (HR) monitoring (flex-HR method) and physical activity level (PAL) calculation was based on BMR. Energy, protein and fat intakes were measured by weighing food on a single day. Urban subjects were heavier and taller than their rural counterparts; significant differences were found in stature in men (P < 0.05) and body weight in women (P < 0.05). Urban subjects had longer sedentary periods (HR < or = flex-HR) and shorter active periods (HR > flex-HR) than rural subjects. Consequently, the former had lower TEE and PAL than the latter; significant differences were found in women (TEE, P < 0.05, PAL, P < 0.01) but not in men. Total daily energy intake and TEE were well balanced (<7 %) in all groups, whereas protein and fat intakes were considerably higher in urban subjects than rural subjects. Reduced PAL and increased fat intake by urban dwellers may increase the risks of obesity and chronic degenerative diseases.

Diet among the Huli in Papua New Guinea highlands when they were influenced by the extended rainy period

Household food consumption surveys (weighed records for 7 days) were conducted in two Huli‐speaking communities, Heli in the slope zone and Wenani in the flat plain, in Papua New Guinea Highlands when their food productivity had decreased after an extended rainy period in 1994. Despite lowered productivity of garden crops in both communities, daily adult male energy and protein intakes in Wenani (12930 kJ, 3090 kcal and 56 g, respectively) exceeded the requirement and safe levels by FAO/WHO/UNU (1985), whereas those in Heli (7750 kJ, 1852 kcal and 35 g) were below both levels. The difference was mostly attributable to three times higher productivity of food energy in the normal period in Wenani than in Heli. The findings are relevant to the maintenance of food security among Papua New Guinea Highlanders.

Impacts of selective logging on New Georgia Island, Solomon Islands evaluated using very-high-resolution satellite (IKONOS) data

SUMMARY Selective harvest has become a dominant method of commercial logging in tropical rainforests of the AsiaPacific region. Although it has usually been recognized that this method minimizes the impact on forest because of the limited number of trees harvested and slight effects on growth of unharvested trees, recent reports suggest that its damage is potentially serious. This study aimed to evaluate the effects of a selective logging operation in 1993--1994 on customary land (2024ha)ofNewGeorgiaIsland,SolomonIslands.Georeferenced IKONOS panchromatic (1-m resolution) and multispectral (4-m resolution) images from 2002 (the post-loggingperiod) and aerial photographs (2.5 m pixels, original scale: 1:25000) from 1991 (the prelogging period) were analysed by means of supervised classification and on-screen visual interpretation, in association with detailed field observation. The area deforested by selective logging was 88 ha (95% confidence limits:79--98ha),accounting for7.4%ofthe original forest and thus causing substantial damage.

Physical activity and subsistence pattern of the Huli, a Papua New Guinea Highland population

Several studies on human energetics have been conducted in developed and developing countries, but very few simultaneously measured time use and energy expenditure. Only a few quantitatively compared subsistence patterns between rural and urban dwellers of an identical population. Here we present the daily physical activity level (PAL), physical exertion, time, and energy expenditure in contrasting subsistence/occupational activities of Papua New Guinea Highlanders, comparing 27 rural villagers (15 men, 12 women) who maintained traditional subsistence agriculture, with 29 urban migrants (14 men, 15 women) who engaged in cash-earning work. A large sex inequality in the division of labor was noted between rural males and females, but not among urban dwellers. Rural-urban comparison indicated sex differences in urbanization. For urban men, the reduction of physical exertion level during work, from energy-consuming agricultural work to sedentary cash-earning work, together with significantly extended work time (by 261 min/day, P < 0.001), led to an increase in work energy expenditure (15-29% of PAL). In contrast, urban women who spent almost equal time at work relative to rural women showed a lower energy expenditure (18% compared to 26% of PAL). The associations with urbanization included a gain in body weight (by 6.4 kg for either sex) and reduced PAL (by 7%, not significant in men; 13%, P < 0.01 in women). Further research is needed to elucidate the effects of urbanization on time use, energy expenditure, and PAL, by comparing rural residents with urban migrants in the same population.

Using shadows in high-resolution imagery to determine building height

This article presents a method for determining building height using shadows in remotely sensed data. The approach classifies building shadows based on their relative within-scene characteristics and spatial context, rules for which are determined empirically against geolocated photographs of the study area. The formal heuristic is described. This method complements existing approaches for extracting building heights that require precise specification of the geometric characteristics of the remotely sensed data and/or large amounts of ancillary data. The approach is suitable for analyses which may only require approximate measures of building height such as those found in many other domains.

Energy expenditure, physical exertion and time allocation among Huli-speaking people in the Papua New Guinea Highlands.

Objectives: The study aimed to (1) elucidate the energetic adaptations of Huli people by comparing the three sub-populations in relation to their diversified natural and socioeconomic environment, based on energy expenditure and time allocation data; and (2) assess the applicability of a new index of physical exertion levels of activities (physical exertion index: PEI). Research design and methods: Married males and females (n = 43) were selected, including 14 from a hilly village, 13 from a flat swampy village and 16 migrants to a town. Continuous heart rate (HR) monitoring, in conjunction with minute-by-minute observation of activities, was undertaken. Total energy expenditure was assessed by flex-HR method and physical activity level (PAL) was calculated as multiples of basal metabolic rate. Observed activities were divided into 15 categories and the PEI was calculated for each: PEI= (mean HR of a categorized activity)/(flex HR) x 100. Results : No significant difference was found in PAL among the three sub-populations: 1.77, 1.92 and 1.81 for men and 1.78, 1.98 and 1.66 for women in hilly and flat villages, and a town, respectively. The comparison of the two village groups revealed that hilly terrain did not affect substantially the physical intensity of agricultural activities. On the other hand, the town migrants were engaged in sedentary paid jobs and these were less energy consuming than agricultural work. However, the different energy costs between paid jobs and agricultural work were offset by longer work time in the town group than in the two village groups (251 vs 50 or 70 min in males; 258 vs 152 or 138 min in females), resulting in similar PAL in the three groups. Conclusions: Despite contrasting natural and social environments, no significant difference was found in daily physical activity level among the three sub-populations (two villages and a town) of Huli-speaking people in Papua New Guinea Highlands.OBJECTIVES The study aimed to (1) elucidate the energetic adaptations of Huli people by comparing the three sub-populations in relation to their diversified natural and socioeconomic environment, based on energy expenditure and time allocation data; and (2) assess the applicability of a new index of physical exertion levels of activities (physical exertion index: PEI). RESEARCH DESIGN AND METHODS Married males and females (n = 43) were selected, including 14 from a hilly village, 13 from a flat swampy village and 16 migrants to a town. Continuous heart rate (HR) monitoring, in conjunction with minute-by-minute observation of activities, was undertaken. Total energy expenditure was assessed by flex-HR method and physical activity level (PAL) was calculated as multiples of basal metabolic rate. Observed activities were divided into 15 categories and the PEI was calculated for each: PEI = (mean HR of a categorized activity)/(flex HR) x 100. RESULTS No significant difference was found in PAL among the three sub-populations: 1.77, 1.92 and 1.81 for men and 1.78, 1.98 and 1.66 for women in hilly and flat villages, and a town, respectively. The comparison of the two village groups revealed that hilly terrain did not affect substantially the physical intensity of agricultural activities. On the other hand, the town migrants were engaged in sedentary paid jobs and these were less energy consuming than agricultural work. However, the different energy costs between paid jobs and agricultural work were offset by longer work time in the town group than in the two village groups (251 vs 50 or 70 min in males; 258 vs 152 or 138 min in females), resulting in similar PAL in the three groups. CONCLUSIONS Despite contrasting natural and social environments, no significant difference was found in daily physical activity level among the three sub-populations (two villages and a town) of Huli-speaking people in Papua New Guinea Highlands.

Evaluation of colorimetric detection methods for Shigella, Salmonella, and Vibrio cholerae by loop-mediated isothermal amplification

We evaluated loop-mediated isothermal amplification end-point detection methods for Salmonella, Shigella, and Vibrio cholerae. Detection sensitivities were comparable to real-time PCR methods. The colorimetric dyes hydroxynaphthol blue and SYBR Green I showed increased sensitivity when compared to visual and automated turbidity readings. End-point colorimetric dyes promise great utility in developing settings.