Question

Phthalates are present in many diverse products, including insect repellents, body lotions, perfumes, and food packaging. Because animal experiments suggest that phthalates may have an adverse effect on the male reproductive system, a group of infertility specialists decided to conduct a case-control study on phthalate exposure and sperm abnormalities in adult men.100 cases with sperm abnormalities and 100 controls were identified and enrolled from among patients at their infertility clinic. 30 cases and 10 controls had high urinary phthalate levels; the remainder had normal urinary phthalate levels.

Use these data to calculate the odds ratio describing the relationship between phthalate levels and sperm abnormalities.

Answer 1

To calculate the odds ratio describing the relationship between phthalate levels and sperm abnormalities, we need to compare the number of cases and controls with high phthalate levels and without high phthalate levels. Using the provided data, the odds ratio is calculated to be 6.43.

Step-by-step explanation:

To calculate the odds ratio describing the relationship between phthalate levels and sperm abnormalities, we need to use the data provided. In this case-control study, there were 100 cases with sperm abnormalities and 100 controls. Among the cases, 30 had high urinary phthalate levels and among the controls, 10 had high urinary phthalate levels.

To calculate the odds ratio, we first determine the number of cases with high phthalate levels who have sperm abnormalities (30) and the number of controls with high phthalate levels who do not have sperm abnormalities (10). We then determine the number of cases without high phthalate levels who have sperm abnormalities (70) and the number of controls without high phthalate levels who do not have sperm abnormalities (90).

The odds ratio is calculated by dividing the odds of having sperm abnormalities in the high phthalate group (30/10) by the odds of having sperm abnormalities in the normal phthalate group (70/90): (30/10) / (70/90) = 6.43