Primer of Epidemiology IV. Study designs II: Interventional or experimental designs

In this article, we describe experimental study designs and focus on randomized controlled trials. Experimental studies are intervention studies in which the investigator tests a new treatment on a selected group of patients. In a controlled design, the effects of an intervention (new treatment) are measured by comparing the outcome in the experimental group with that in a control group. Experimental studies are similar to cohort studies except that the exposure is a deliberate change (intervention) made by the researcher in one group of participants and it overcomes confounding because the treatment is assigned randomly. Further, we discuss various types of randomization (random sequence allocation) and importance of allocation concealment and blinding for proper assessment of outcomes in randomized trials.

Functional Disability Among Elderly Persons in a Rural Area of Haryana.

Background: The number and proportion of elderly persons is increasing, in India, as well as the world. Disability is an important indicator to measure disease burden in this group. While some chronic conditions may not be amenable to complete cure, their functional disabilities can be improved with timely and appropriate management. Objectives: The objective of the following study is to estimate the prevalence of functional disability and study its association with socio-demographic variables and self-reported chronic conditions among elderly persons in a rural area of Haryana. Materials and Methods: All persons aged 60 years and above in the randomly selected six clusters were included in this community-based cross-sectional study. Information was collected on socio-demographic variables and selfreported chronic conditions. Functional disability was defi ned as having disability in activities of daily living, or blindness or hearing impairment, or a combination of these. In multivariate analysis, backward stepwise logistic regression was carried out to study the association between the independent and dependent variables, after adjusting for confounding variables. Results: Among the 836 participants studied, the prevalence of functional disability was estimated to be 37.4% (95% confi dence interval: 34.2, 40.7). The prevalence was less among men (35.9%) than women (38.8%). The prevalence increased with age, was more common among persons who were not currently married, had diabetes and chronic obstructive pulmonary disease. Conclusion: Functional disability is common among elderly persons in the rural area. Community-based interventions are needed tto address them. Management of chronic conditions should include prevention and control of associated disability.

In-vitro cancer cell cytotoxicity and alpha amylase inhibition effect of seven tropical fruit residues

Objective:To determine quantitative phytochemical, anticancer and antidiabetic effect of seven Indian tropical fruit residues. Methods:In-vitro cytotoxic activity (IC50) was evaluated against cervical cancer cells (HeLa), breast cancer cells (MCF-7), hepatocellular carcinoma cells (HepG-2) and bone sarcoma cells (MG-63) and alpha amylase inhibition assay was used for antidiabetic activity. Results: Results of phytochemical analysis revealed that all residues contained remarkable amount of alkaloid, saponin, tannin and flavonoid. Notable cancer cell growth inhibition was observed for the extract from Carissa carandas pomace and Litchi sinensis seeds with IC50 values ranged from 56.72 to 89.24 μg/mL. Alpha amylase inhibition assay was measured at six different concentrations (5, 10, 25, 50, 100 and 200 mg/mL) by using different solvent extract. Results showed that Carissa carandas possessed best activity with IC50 value as 29.66 mg/mL followed by other residues in methanol extract. Conclusions:Study suggests that these fruit residues demonstrate promising antidiabetic and anticancer activity that substantiated its ethno medicinal use and may provide new molecules for the treatment of these diseases.

Soil and its economic implications in India.

Soil is a complex media formed by a porous matrix, in which air, water and biota occur together and its severe degradation is another reality that depends on several factors. Soil problems are influenced by the diversity, distribution and specific vulnerability of soils. They also depend on geology, relief and climate and in India, soil conditions are no good and are even further worsen by human activities. The different ways to categorize impacts includes the on-site and off-site impacts, cost of suffered damage and damage avoidance cost, direct & indirect use values and the non-use values (not quantified). The five major cost categories are: PC, RC – on-site costs, SC, DC – off-site costs & NC – non-use costs. Assessment of economic impacts of soil degradation have revealed that off-site costs (SC+DC) exceed on-site costs (PC+RC) by 12:1 and the cost of suffered damage (PC+SC) was higher than damage avoidance cost (RC+DC). In the present scenario, we have already realized the fact of “Down to earth, down to basics” – solving soil problems will help solve other problems at the National and global levels. As soil has multiple users, consideration of soil has to be integrated at different levels. There is a need for administrative (from local to National and global), sectoral (sectors and other environmental issues) and geographical integration (landscapes, urban, rural, mountain and coastal areas) of both soil assessment approaches and soil protection policies. There are appropriate actions to be taken at all administrative levels, from land planning at the local and sub-national levels, to the set-up of environmental and sectoral policies at the national levels, and the launch of initiatives on a global scale.