## Facts

- A U.S. Army Reservist injured both knees during active duty for training in 1978.
- VA granted service connection for bilateral knee chondromalacia and later for a low back disability and bilateral hip arthritis.
- The veteran reported that pain, sedating pain medication, and resulting mobility limits contributed to weight gain.
- In 2009, the veteran sought secondary service connection for hypertension and a sleep disorder later diagnosed as mild obstructive sleep apnea.
- A VA examiner linked sleep apnea and hypertension to weight gain/obesity.
- The Board sought a medical opinion addressing whether obesity, implicated as the cause of hypertension and sleep apnea, was caused or aggravated by service-connected disabilities.
- VA obtained an opinion addressing only whether the service-connected orthopedic disabilities caused obesity; the examiner found no clear cause-and-effect relationship.
- Relying on that opinion, the Board denied secondary service connection for hypertension and sleep apnea.

## Issues

1. Whether obesity may serve as an “intermediate step” for secondary service connection when a service-connected disability aggravates, not only causes, obesity under 38 C.F.R. § 3.310.
2. Whether the Board erred by relying on a medical opinion and reasons-or-bases that failed to address aggravation of obesity as part of the secondary service-connection theory.

## Decision

- The Court held obesity may be an intermediate step in a secondary service-connection chain when a service-connected disability either causes or aggravates obesity.
- The Court found the Board’s decision inadequate because it relied on a medical opinion limited to causation and did not address aggravation.
- The Court vacated the Board’s denial of service connection for hypertension and sleep apnea and remanded for further proceedings.

## Legal Principles

- Secondary service connection under 38 C.F.R. § 3.310 includes both (a) proximate causation and (b) aggravation of a non-service-connected condition by a service-connected disability.
- Obesity is not a compensable disease or injury for direct service connection, but it may function as an intermediate step between a service-connected disability and a claimed secondary disability.
- When the record reasonably raises obesity as an intermediate step, adjudication must consider both whether the service-connected disability caused obesity and whether it aggravated obesity.
- A medical opinion and Board statement of reasons or bases are inadequate if they address only causation and omit aggravation where aggravation is a legally viable and reasonably raised theory.

## Conclusion

The Court required VA to consider obesity as an intermediate step in secondary service connection on both causation and aggravation theories, and it vacated and remanded where the Board relied on an opinion that failed to address aggravation of obesity by service-connected disabilities.


Walsh v. Wilkie, 32 Vet. App. 300 (2020)