Linkages between biodiversity loss and human health: a global indicator analysis.

The association between health and biodiversity loss was explored by means of regression analysis on a global scale, with control for confounding by socio-economic developments. For this we selected indicators of human health (life expectancy, disability adjusted life expectancy, infant mortality rate and percentage low-birthweight babies), biodiversity (percentage threatened species, current forest as a percentage of original forest, percentage of land highly disturbed by man) and socio-economic development (health expenditure as percentage of GNP, percentage one-year olds immunized, illiteracy rate, GNP per capita and development grade) on a country level. After controlling for relevant socio-economic confounders, both current forest as a percentage of original forest and the percentage of land highly disturbed by human activities had no relationship with one of the health indicators. The logarithm of the percentage threatened species, showed a positive association with life expectancy and disability adjusted life expectancy. The present study was not able to provide any empirical proof of a negative association between loss of biodiversity and human health at the global scale. This does not mean, however, that no such relationship exists, because there may be several reasons for our findings, like possible non-linearity of the relationship, lack of suitable indicators, non-randomness in the sample of countries and the limitations of regression analysis in proving causality.

The impact of heat waves and cold spells on mortality rates in the Dutch population.

We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979-1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward displacement of mortality. We found a V-like relationship between mortality and temperature, with an optimum temperature value (e.g., average temperature with lowest mortality rate) of 16.5 degrees C for total mortality, cardiovascular mortality, respiratory mortality, and mortality among those [Greater and equal to] 65 year of age. For mortality due to malignant neoplasms and mortality in the youngest age group, the optimum temperatures were 15.5 degrees C and 14.5 degrees C, respectively. For temperatures above the optimum, mortality increased by 0.47, 1.86, 12.82, and 2.72% for malignant neoplasms, cardiovascular disease, respiratory diseases, and total mortality, respectively, for each degree Celsius increase above the optimum in the preceding month. For temperatures below the optimum, mortality increased 0.22, 1.69, 5.15, and 1.37%, respectively, for each degree Celsius decrease below the optimum in the preceding month. Mortality increased significantly during all of the heat waves studied, and the elderly were most effected by extreme heat. The heat waves led to increases in mortality due to all of the selected causes, especially respiratory mortality. Average total excess mortality during the heat waves studied was 12.1%, or 39.8 deaths/day. The average excess mortality during the cold spells was 12.8% or 46.6 deaths/day, which was mostly attributable to the increase in cardiovascular mortality and mortality among the elderly. The results concerning the forward displacement of deaths due to heat waves were not conclusive. We found no cold-induced forward displacement of deaths.