Individuals who live below the poverty line get seriously ill more often than
those who do not. what could be the hidden variable in this situation?

the people living below poverty are not getting the same medical advantages of people who are above poverty level

Explanation:

ANSWER:    

People  who live below  poverty  have difficulty  in gaining access to health care system and are at increased risk of various diseases because of the  environment they live, food they eat and  also due to  the  difficulty gaining access to health care system

Explanation:

Individuals  living in poverty usually doesn't have access to good health care with professional doctors.  During pregnancy mothers have insufficient nutrition and prenatal care . Another fact that influences the health of poor people is their living condition.

Poor living conditions lead to the increase in growth and spreading of  diseases. Forcing one to work harder also affects health due to stress. A lack of clean water, sanitation and hygiene is also a reason that affects the health of the individuals living below poverty line .

answer: no, they are not.*

although rubber bands that contain excessive amounts of dye, toxins, or additives are sometimes toxic, most rubber bands do not cause any health issues. since they are typically made of latex, (a natural substance that is extracted from trees) they are not dangerous in any way if you chew them or accidentally ingest a piece of rubber band. however, chewing rubber bands does pose a choking hazard and is not a good habit to have.

*depending on the type of rubber band. the typical rubber bands that you see at stores are not toxic, but other types of rubber or latex that contains certain chemicals may be unhealthy and hazardous.