On Nov. 15, it is anticipated that the world will surpass a monumental population milestone: 8 billion humans living on the planet. This is a big deal because it means that 8 billion people already require healthcare goods and/or services or will at some point.

The global population is expected to surpass 10 billion around 2050, and the share of those aged 65 years and older is set to surge from 10% to 16% by 2050. This should translate into higher revenue and profits for healthcare companies, which could be used for further research and development to enhance patients' quality of life around the world.

Pharma giant Pfizer (PFE) and medical device maker Medtronic (MDT 1.83%) should both be major beneficiaries of this demographic trend. Here's why each stock is a buy for income investors at this time.

1. Pfizer

Pfizer is a mega-cap pharmaceutical company, selling its products in more than 125 countries and employing 79,000 employees. The medicine and vaccine maker is most well-known by consumers for its best-selling COVID-19 vaccine, Comirnaty, co-developed with German partner BioNTech. But with eight other products positioned to eclipse $1 billion in sales in 2022, in addition to Comirnaty and antiviral COVID-19 treatment Paxlovid, Pfizer is more than just the undisputed leader in COVID-19 vaccines and therapeutics.

Pfizer forecasts it will be launching 19 new indications in the next year and a half. These product launches are projected to generate the company more than $20 billion in annual sales by 2030. Since sales of COVID-19 products will likely drop dramatically in the coming quarters, this diversification will be a huge positive.

Looking further, Pfizer had 112 projects in clinical development as of earlier this month. This pipeline should be more than enough to keep revenue and earnings moving higher over the long run.

Pfizer's 3.4% dividend yield is double the S&P 500 index's 1.7% yield. And with the dividend payout ratio under 25%, the company should be able to grow its market-beating dividend in the years to come.

Finally, the stock is trading at a forward price-to-earnings (P/E) ratio of 9.1. This is well below the general drug manufacturer average forward P/E ratio of 11.8. Even accounting for the temporary dip in revenue and earnings in the foreseeable future, this is arguably already priced into the stock.

A doctor meets with a patient for an appointment.

Image source: Getty Images.

2. Medtronic

According to market research firm Precedence Research, the growing and aging global population bodes well for the global medical devices industry. In fact, the firm predicts that the industry will compound 5.5% annually from $550 billion in 2021 to $850 billion by 2030.

Among the industry beneficiaries should be Ireland-based Medtronic, whose products served 76 million patients with over 70 health conditions. These medical devices range from insulin pumps for diabetes to spinal cord stimulators for chronic pain.

The company has more than 235 clinical trials for prospective medical devices currently in progress throughout treatment areas such as cardiovascular, diabetes, medical-surgical, and neuroscience. That's why analysts believe Medtronic will deliver 12.7% annual earnings growth in the next five years. For context, this is superior to the consensus growth rate of 11.5% for the medical devices industry.

Meanwhile, the stock offers a market-topping dividend yield of 3.4%. With a dividend payout ratio of 45.4%, the dividend could grow at least in the high single digits over the next few years.

Shares of the stock trade today at a forward P/E ratio of 14.5, well below the medical devices industry's average of 23. That is a downright steal of a valuation, making Medtronic an attractive pick for dividend growth investors.