Consumers in their fifties and above are driving an emerging passion for ethical shopping in the US, a study has claimed.

Almost half of US consumers consider at least one sustainability factor in selecting goods and choosing where to shop, a survey from Information Resources suggested.

Contrary to assumptions that sustainability is a youth-oriented phenomenon, the survey showed consumers aged 55 and older are the driving force behind growth, with the time and resources to seek out and purchase speciality items and premium-priced products.

The study highlighted an increasing focus on environmental and ethical issues is creating a growing US market for sustainable products and packaging.

A fifth of the 22,000 polled claimed to consider at least two factors when shopping, with some 30% of respondents looking for eco-friendly products and packaging.

Up to a quarter consider fair trade practices along with eco-friendly or organic designations in selecting where to shop, and nearly 40% of consumers search specifically for organic products.