BarceloNa: Earphones embedded in pearl earrings, a smartwatch that measures body temperature, a diamond ring that monitors sleep patterns: The wearable gadgets market has boomed as the pandemic boosts interest in health monitoring and working from home. While worldwide sales of smartphones slumped last year, a record 527 million wearables were sold in 2020, up from 384 million in 2019, according to research firm Strategy Analytics. It was the first time that global wearable sales topped half a billion and analysts expect the trend to continue, with the firm forecasting the devices will overtake smartphone sales by the end of the decade. The surge in wearables sales was in focus at the four-day Mobile World Congress, the telecom industry´s biggest annual gathering, which wraps up Thursday in Barcelona. Ear-worn devices such as earbuds, which can be used to make calls and listen to music, accounted for nearly two-thirds of global wearable sales last year as people working from home upgraded their headphones for video calling.