Floods Have Big Downstream Effects on People’s Health

Long after floodwaters recede, the impact of flooding on the health of older adults is profound, new research shows.

Rates of hospitalizations for a range of conditions affecting the skin and nervous system, as well as poisonings, injuries or mental health woes were all elevated during and after major floods, according to a new data analysis.

There’s much that can be done to prevent many of these hospitalizations, however.

“Targeted outreach and robust evacuation planning for vulnerable populations, such as older individuals, along with community-based alert systems, are crucial to minimizing health impacts,” said a group led by Sarika Aggarwal. She’s a PhD candidate at the Harvard T.H. Chan School of Public Health.

The team published its findings July 30 in The Lancet Planetary Health.

The study looked at Medicare hospitalization data from 2000 to 2016, then compared it to information from the Global Flood Database on flooding in the U.S.

The study focused on hospitalizations for patients aged 65 or older, covering 13 disease conditions. The hospitalizations all occurred within four weeks of a flooding event.

More than 4.5 million hospitalizations linked to 72 “significant flood events” were part of the analysis.

Aggarwal’s team observed elevated rates of hospitalizations for seniors from a number of causes:

A 3.1% rise in admissions for skin diseases
A 2.5% rise in admissions for nervous system disorders
A 1.1% rise in admissions for injuries or poisonings

The researchers noted that older Americans are particularly prone to flood-linked injuries and illness, because they tend to have weakened immune systems, are less mobile and may also have pre-existing conditions such as dementia.

Skin conditions can arise when older people come into contact with polluted water, face unsanitary environments or are placed into crowded shelters, the researchers said.

Nervous system disorders can occur after flood-linked brain injuries trigger seizures, for example, and fatigue and stress might also raise the odds of seizures in seniors diagnosed with epilepsy.

Delays in getting care or poorer living conditions may aggravate a number of musculoskeletal conditions, Aggarwal and colleagues added.

“The findings of this study provide crucial new insights into the diverse, and previously underappreciated, health consequences of floods in older adults and can guide flood-specific resilience-building efforts to protect public health under climate change,” the researchers concluded.

Better preparation before flooding hits can be life-saving.

“Hospital infrastructure should be equipped to function during flood events by moving essential components above flood levels, and mobile medicine units and telemedicine can serve as effective alternatives if access to hospitals is temporarily eliminated,” the research team advised.

Even drones can help.

“Drones can also deliver essential medical supplies to flood-affected hospitals or help identify safe evacuation routes in real time to guide emergency responders,” the team noted.

More information

There’s more about how to prepare for major floods at the U.S. Centers for Disease Control and Prevention.

SOURCE: Columbia University Mailman School of Public Health, news release, July 30, 2025

Source: HealthDay